www/plugins-dist/medias/lib/getid3/module.audio-video.mpeg.php

   1 <?php
   2
   3 /////////////////////////////////////////////////////////////////
   4 /// getID3() by James Heinrich <info@getid3.org>               //
   5 //  available at https://github.com/JamesHeinrich/getID3       //
   6 //            or https://www.getid3.org                        //
   7 //            or http://getid3.sourceforge.net                 //
   8 //  see readme.txt for more details                            //
   9 /////////////////////////////////////////////////////////////////
  10 //                                                             //
  11 // module.audio-video.mpeg.php                                 //
  12 // module for analyzing MPEG files                             //
  13 // dependencies: module.audio.mp3.php                          //
  14 //                                                            ///
  15 /////////////////////////////////////////////////////////////////
  16
  17 getid3_lib::IncludeDependency(GETID3_INCLUDEPATH.'module.audio.mp3.php', __FILE__, true);
  18
  19 class getid3_mpeg extends getid3_handler
  20 {
  21
  22         const START_CODE_BASE       = "\x00\x00\x01";
  23         const VIDEO_PICTURE_START   = "\x00\x00\x01\x00";
  24         const VIDEO_USER_DATA_START = "\x00\x00\x01\xB2";
  25         const VIDEO_SEQUENCE_HEADER = "\x00\x00\x01\xB3";
  26         const VIDEO_SEQUENCE_ERROR  = "\x00\x00\x01\xB4";
  27         const VIDEO_EXTENSION_START = "\x00\x00\x01\xB5";
  28         const VIDEO_SEQUENCE_END    = "\x00\x00\x01\xB7";
  29         const VIDEO_GROUP_START     = "\x00\x00\x01\xB8";
  30         const AUDIO_START           = "\x00\x00\x01\xC0";
  31
  32         /**
  33          * @return bool
  34          */
  35         public function Analyze() {
  36                 $info = &$this->getid3->info;
  37
  38                 $info['fileformat'] = 'mpeg';
  39                 $this->fseek($info['avdataoffset']);
  40
  41                 $MPEGstreamData = $this->fread($this->getid3->option_fread_buffer_size);
  42                 $MPEGstreamBaseOffset = 0; // how far are we from the beginning of the file data ($info['avdataoffset'])
  43                 $MPEGstreamDataOffset = 0; // how far are we from the beginning of the buffer data (~32kB)
  44
  45                 $StartCodeValue     = false;
  46                 $prevStartCodeValue = false;
  47
  48                 $GOPcounter = -1;
  49                 $FramesByGOP = array();
  50                 $ParsedAVchannels = array();
  51
  52                 do {
  53 //echo $MPEGstreamDataOffset.' vs '.(strlen($MPEGstreamData) - 1024).'<Br>';
  54                         if ($MPEGstreamDataOffset > (strlen($MPEGstreamData) - 16384)) {
  55                                 // buffer running low, get more data
  56 //echo 'reading more data<br>';
  57                                 $MPEGstreamData .= $this->fread($this->getid3->option_fread_buffer_size);
  58                                 if (strlen($MPEGstreamData) > $this->getid3->option_fread_buffer_size) {
  59                                         $MPEGstreamData = substr($MPEGstreamData, $MPEGstreamDataOffset);
  60                                         $MPEGstreamBaseOffset += $MPEGstreamDataOffset;
  61                                         $MPEGstreamDataOffset  = 0;
  62                                 }
  63                         }
  64                         if (($StartCodeOffset = strpos($MPEGstreamData, self::START_CODE_BASE, $MPEGstreamDataOffset)) === false) {
  65 //echo 'no more start codes found.<br>';
  66                                 break;
  67                         } else {
  68                                 $MPEGstreamDataOffset = $StartCodeOffset;
  69                                 $prevStartCodeValue = $StartCodeValue;
  70                                 $StartCodeValue = ord(substr($MPEGstreamData, $StartCodeOffset + 3, 1));
  71 //echo 'Found "'.strtoupper(dechex($StartCodeValue)).'" at offset '.($MPEGstreamBaseOffset + $StartCodeOffset).' ($MPEGstreamDataOffset = '.$MPEGstreamDataOffset.')<br>';
  72                         }
  73                         $MPEGstreamDataOffset += 4;
  74                         switch ($StartCodeValue) {
  75
  76                                 case 0x00: // picture_start_code
  77                                         if (!empty($info['mpeg']['video']['bitrate_mode']) && ($info['mpeg']['video']['bitrate_mode'] == 'vbr')) {
  78                                                 $bitstream = getid3_lib::BigEndian2Bin(substr($MPEGstreamData, $StartCodeOffset + 4, 4));
  79                                                 $bitstreamoffset = 0;
  80
  81                                                 $PictureHeader = array();
  82
  83                                                 $PictureHeader['temporal_reference']  = self::readBitsFromStream($bitstream, $bitstreamoffset, 10); // 10-bit unsigned integer associated with each input picture. It is incremented by one, modulo 1024, for each input frame. When a frame is coded as two fields the temporal reference in the picture header of both fields is the same. Following a group start header the temporal reference of the earliest picture (in display order) shall be reset to zero.
  84                                                 $PictureHeader['picture_coding_type'] = self::readBitsFromStream($bitstream, $bitstreamoffset,  3); //  3 bits for picture_coding_type
  85                                                 $PictureHeader['vbv_delay']           = self::readBitsFromStream($bitstream, $bitstreamoffset, 16); // 16 bits for vbv_delay
  86                                                 //... etc
  87
  88                                                 $FramesByGOP[$GOPcounter][] = $PictureHeader;
  89                                         }
  90                                         break;
  91
  92                                 case 0xB3: // sequence_header_code
  93                                         /*
  94                                         Note: purposely doing the less-pretty (and probably a bit slower) method of using string of bits rather than bitwise operations.
  95                                               Mostly because PHP 32-bit doesn't handle unsigned integers well for bitwise operation.
  96                                               Also the MPEG stream is designed as a bitstream and often doesn't align nicely with byte boundaries.
  97                                         */
  98                                         $info['video']['codec'] = 'MPEG-1'; // will be updated if extension_start_code found
  99
 100                                         $bitstream = getid3_lib::BigEndian2Bin(substr($MPEGstreamData, $StartCodeOffset + 4, 8));
 101                                         $bitstreamoffset = 0;
 102
 103                                         $info['mpeg']['video']['raw']['horizontal_size_value']       = self::readBitsFromStream($bitstream, $bitstreamoffset, 12); // 12 bits for horizontal frame size. Note: horizontal_size_extension, if present, will add 2 most-significant bits to this value
 104                                         $info['mpeg']['video']['raw']['vertical_size_value']         = self::readBitsFromStream($bitstream, $bitstreamoffset, 12); // 12 bits for vertical frame size.   Note: vertical_size_extension,   if present, will add 2 most-significant bits to this value
 105                                         $info['mpeg']['video']['raw']['aspect_ratio_information']    = self::readBitsFromStream($bitstream, $bitstreamoffset,  4); //  4 bits for aspect_ratio_information
 106                                         $info['mpeg']['video']['raw']['frame_rate_code']             = self::readBitsFromStream($bitstream, $bitstreamoffset,  4); //  4 bits for Frame Rate id code
 107                                         $info['mpeg']['video']['raw']['bitrate']                     = self::readBitsFromStream($bitstream, $bitstreamoffset, 18); // 18 bits for bit_rate_value (18 set bits = VBR, otherwise bitrate = this value * 400)
 108                                         $marker_bit                                                  = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); // The term "marker_bit" indicates a one bit field in which the value zero is forbidden. These marker bits are introduced at several points in the syntax to avoid start code emulation.
 109                                         $info['mpeg']['video']['raw']['vbv_buffer_size']             = self::readBitsFromStream($bitstream, $bitstreamoffset, 10); // 10 bits vbv_buffer_size_value
 110                                         $info['mpeg']['video']['raw']['constrained_param_flag']      = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: constrained_param_flag
 111                                         $info['mpeg']['video']['raw']['load_intra_quantiser_matrix'] = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: load_intra_quantiser_matrix
 112
 113                                         if ($info['mpeg']['video']['raw']['load_intra_quantiser_matrix']) {
 114                                                 $bitstream .= getid3_lib::BigEndian2Bin(substr($MPEGstreamData, $StartCodeOffset + 12, 64));
 115                                                 for ($i = 0; $i < 64; $i++) {
 116                                                         $info['mpeg']['video']['raw']['intra_quantiser_matrix'][$i] = self::readBitsFromStream($bitstream, $bitstreamoffset,  8);
 117                                                 }
 118                                         }
 119                                         $info['mpeg']['video']['raw']['load_non_intra_quantiser_matrix'] = self::readBitsFromStream($bitstream, $bitstreamoffset,  1);
 120
 121                                         if ($info['mpeg']['video']['raw']['load_non_intra_quantiser_matrix']) {
 122                                                 $bitstream .= getid3_lib::BigEndian2Bin(substr($MPEGstreamData, $StartCodeOffset + 12 + ($info['mpeg']['video']['raw']['load_intra_quantiser_matrix'] ? 64 : 0), 64));
 123                                                 for ($i = 0; $i < 64; $i++) {
 124                                                         $info['mpeg']['video']['raw']['non_intra_quantiser_matrix'][$i] = self::readBitsFromStream($bitstream, $bitstreamoffset,  8);
 125                                                 }
 126                                         }
 127
 128                                         $info['mpeg']['video']['pixel_aspect_ratio']      =     self::videoAspectRatioLookup($info['mpeg']['video']['raw']['aspect_ratio_information']); // may be overridden later if file turns out to be MPEG-2
 129                                         $info['mpeg']['video']['pixel_aspect_ratio_text'] = self::videoAspectRatioTextLookup($info['mpeg']['video']['raw']['aspect_ratio_information']); // may be overridden later if file turns out to be MPEG-2
 130                                         $info['mpeg']['video']['frame_rate']              =       self::videoFramerateLookup($info['mpeg']['video']['raw']['frame_rate_code']);
 131                                         if ($info['mpeg']['video']['raw']['bitrate'] == 0x3FFFF) { // 18 set bits = VBR
 132                                                 //$this->warning('This version of getID3() ['.$this->getid3->version().'] cannot determine average bitrate of VBR MPEG video files');
 133                                                 $info['mpeg']['video']['bitrate_mode'] = 'vbr';
 134                                         } else {
 135                                                 $info['mpeg']['video']['bitrate']      = $info['mpeg']['video']['raw']['bitrate'] * 400;
 136                                                 $info['mpeg']['video']['bitrate_mode'] = 'cbr';
 137                                                 $info['video']['bitrate']              = $info['mpeg']['video']['bitrate'];
 138                                         }
 139                                         $info['video']['resolution_x']       = $info['mpeg']['video']['raw']['horizontal_size_value'];
 140                                         $info['video']['resolution_y']       = $info['mpeg']['video']['raw']['vertical_size_value'];
 141                                         $info['video']['frame_rate']         = $info['mpeg']['video']['frame_rate'];
 142                                         $info['video']['bitrate_mode']       = $info['mpeg']['video']['bitrate_mode'];
 143                                         $info['video']['pixel_aspect_ratio'] = $info['mpeg']['video']['pixel_aspect_ratio'];
 144                                         $info['video']['lossless']           = false;
 145                                         $info['video']['bits_per_sample']    = 24;
 146                                         break;
 147
 148                                 case 0xB5: // extension_start_code
 149                                         $info['video']['codec'] = 'MPEG-2';
 150
 151                                         $bitstream = getid3_lib::BigEndian2Bin(substr($MPEGstreamData, $StartCodeOffset + 4, 8)); // 48 bits for Sequence Extension ID; 61 bits for Sequence Display Extension ID; 59 bits for Sequence Scalable Extension ID
 152                                         $bitstreamoffset = 0;
 153
 154                                         $info['mpeg']['video']['raw']['extension_start_code_identifier'] = self::readBitsFromStream($bitstream, $bitstreamoffset,  4); //  4 bits for extension_start_code_identifier
 155 //echo $info['mpeg']['video']['raw']['extension_start_code_identifier'].'<br>';
 156                                         switch ($info['mpeg']['video']['raw']['extension_start_code_identifier']) {
 157                                                 case  1: // 0001 Sequence Extension ID
 158                                                         $info['mpeg']['video']['raw']['profile_and_level_indication']    = self::readBitsFromStream($bitstream, $bitstreamoffset,  8); //  8 bits for profile_and_level_indication
 159                                                         $info['mpeg']['video']['raw']['progressive_sequence']            = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: progressive_sequence
 160                                                         $info['mpeg']['video']['raw']['chroma_format']                   = self::readBitsFromStream($bitstream, $bitstreamoffset,  2); //  2 bits for chroma_format
 161                                                         $info['mpeg']['video']['raw']['horizontal_size_extension']       = self::readBitsFromStream($bitstream, $bitstreamoffset,  2); //  2 bits for horizontal_size_extension
 162                                                         $info['mpeg']['video']['raw']['vertical_size_extension']         = self::readBitsFromStream($bitstream, $bitstreamoffset,  2); //  2 bits for vertical_size_extension
 163                                                         $info['mpeg']['video']['raw']['bit_rate_extension']              = self::readBitsFromStream($bitstream, $bitstreamoffset, 12); // 12 bits for bit_rate_extension
 164                                                         $marker_bit                                                      = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); // The term "marker_bit" indicates a one bit field in which the value zero is forbidden. These marker bits are introduced at several points in the syntax to avoid start code emulation.
 165                                                         $info['mpeg']['video']['raw']['vbv_buffer_size_extension']       = self::readBitsFromStream($bitstream, $bitstreamoffset,  8); //  8 bits for vbv_buffer_size_extension
 166                                                         $info['mpeg']['video']['raw']['low_delay']                       = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: low_delay
 167                                                         $info['mpeg']['video']['raw']['frame_rate_extension_n']          = self::readBitsFromStream($bitstream, $bitstreamoffset,  2); //  2 bits for frame_rate_extension_n
 168                                                         $info['mpeg']['video']['raw']['frame_rate_extension_d']          = self::readBitsFromStream($bitstream, $bitstreamoffset,  5); //  5 bits for frame_rate_extension_d
 169
 170                                                         $info['video']['resolution_x']          = ($info['mpeg']['video']['raw']['horizontal_size_extension'] << 12) | $info['mpeg']['video']['raw']['horizontal_size_value'];
 171                                                         $info['video']['resolution_y']          = ($info['mpeg']['video']['raw']['vertical_size_extension']   << 12) | $info['mpeg']['video']['raw']['vertical_size_value'];
 172                                                         $info['video']['interlaced']            = !$info['mpeg']['video']['raw']['progressive_sequence'];
 173                                                         $info['mpeg']['video']['interlaced']    = !$info['mpeg']['video']['raw']['progressive_sequence'];
 174                                                         $info['mpeg']['video']['chroma_format'] = self::chromaFormatTextLookup($info['mpeg']['video']['raw']['chroma_format']);
 175
 176                                                         if (isset($info['mpeg']['video']['raw']['aspect_ratio_information'])) {
 177                                                                 // MPEG-2 defines the aspect ratio flag differently from MPEG-1, but the MPEG-2 extension start code may occur after we've already looked up the aspect ratio assuming it was MPEG-1, so re-lookup assuming MPEG-2
 178                                                                 // This must be done after the extended size is known, so the display aspect ratios can be converted to pixel aspect ratios.
 179                                                                 $info['mpeg']['video']['pixel_aspect_ratio']      =     self::videoAspectRatioLookup($info['mpeg']['video']['raw']['aspect_ratio_information'], 2, $info['video']['resolution_x'], $info['video']['resolution_y']);
 180                                                                 $info['mpeg']['video']['pixel_aspect_ratio_text'] = self::videoAspectRatioTextLookup($info['mpeg']['video']['raw']['aspect_ratio_information'], 2);
 181                                                                 $info['video']['pixel_aspect_ratio'] = $info['mpeg']['video']['pixel_aspect_ratio'];
 182                                                                 $info['video']['pixel_aspect_ratio_text'] = $info['mpeg']['video']['pixel_aspect_ratio_text'];
 183                                                         }
 184
 185                                                         break;
 186
 187                                                 case  2: // 0010 Sequence Display Extension ID
 188                                                         $info['mpeg']['video']['raw']['video_format']                    = self::readBitsFromStream($bitstream, $bitstreamoffset,  3); //  3 bits for video_format
 189                                                         $info['mpeg']['video']['raw']['colour_description']              = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: colour_description
 190                                                         if ($info['mpeg']['video']['raw']['colour_description']) {
 191                                                                 $info['mpeg']['video']['raw']['colour_primaries']            = self::readBitsFromStream($bitstream, $bitstreamoffset,  8); //  8 bits for colour_primaries
 192                                                                 $info['mpeg']['video']['raw']['transfer_characteristics']    = self::readBitsFromStream($bitstream, $bitstreamoffset,  8); //  8 bits for transfer_characteristics
 193                                                                 $info['mpeg']['video']['raw']['matrix_coefficients']         = self::readBitsFromStream($bitstream, $bitstreamoffset,  8); //  8 bits for matrix_coefficients
 194                                                         }
 195                                                         $info['mpeg']['video']['raw']['display_horizontal_size']         = self::readBitsFromStream($bitstream, $bitstreamoffset, 14); // 14 bits for display_horizontal_size
 196                                                         $marker_bit                                                      = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); // The term "marker_bit" indicates a one bit field in which the value zero is forbidden. These marker bits are introduced at several points in the syntax to avoid start code emulation.
 197                                                         $info['mpeg']['video']['raw']['display_vertical_size']           = self::readBitsFromStream($bitstream, $bitstreamoffset, 14); // 14 bits for display_vertical_size
 198
 199                                                         $info['mpeg']['video']['video_format'] = self::videoFormatTextLookup($info['mpeg']['video']['raw']['video_format']);
 200                                                         break;
 201
 202                                                 case  3: // 0011 Quant Matrix Extension ID
 203                                                         break;
 204
 205                                                 case  5: // 0101 Sequence Scalable Extension ID
 206                                                         $info['mpeg']['video']['raw']['scalable_mode']                              = self::readBitsFromStream($bitstream, $bitstreamoffset,  2); //  2 bits for scalable_mode
 207                                                         $info['mpeg']['video']['raw']['layer_id']                                   = self::readBitsFromStream($bitstream, $bitstreamoffset,  4); //  4 bits for layer_id
 208                                                         if ($info['mpeg']['video']['raw']['scalable_mode'] == 1) { // "spatial scalability"
 209                                                                 $info['mpeg']['video']['raw']['lower_layer_prediction_horizontal_size'] = self::readBitsFromStream($bitstream, $bitstreamoffset, 14); // 14 bits for lower_layer_prediction_horizontal_size
 210                                                                 $marker_bit                                                             = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); // The term "marker_bit" indicates a one bit field in which the value zero is forbidden. These marker bits are introduced at several points in the syntax to avoid start code emulation.
 211                                                                 $info['mpeg']['video']['raw']['lower_layer_prediction_vertical_size']   = self::readBitsFromStream($bitstream, $bitstreamoffset, 14); // 14 bits for lower_layer_prediction_vertical_size
 212                                                                 $info['mpeg']['video']['raw']['horizontal_subsampling_factor_m']        = self::readBitsFromStream($bitstream, $bitstreamoffset,  5); //  5 bits for horizontal_subsampling_factor_m
 213                                                                 $info['mpeg']['video']['raw']['horizontal_subsampling_factor_n']        = self::readBitsFromStream($bitstream, $bitstreamoffset,  5); //  5 bits for horizontal_subsampling_factor_n
 214                                                                 $info['mpeg']['video']['raw']['vertical_subsampling_factor_m']          = self::readBitsFromStream($bitstream, $bitstreamoffset,  5); //  5 bits for vertical_subsampling_factor_m
 215                                                                 $info['mpeg']['video']['raw']['vertical_subsampling_factor_n']          = self::readBitsFromStream($bitstream, $bitstreamoffset,  5); //  5 bits for vertical_subsampling_factor_n
 216                                                         } elseif ($info['mpeg']['video']['raw']['scalable_mode'] == 3) { // "temporal scalability"
 217                                                                 $info['mpeg']['video']['raw']['picture_mux_enable']                     = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: picture_mux_enable
 218                                                                 if ($info['mpeg']['video']['raw']['picture_mux_enable']) {
 219                                                                         $info['mpeg']['video']['raw']['mux_to_progressive_sequence']        = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: mux_to_progressive_sequence
 220                                                                 }
 221                                                                 $info['mpeg']['video']['raw']['picture_mux_order']                      = self::readBitsFromStream($bitstream, $bitstreamoffset,  3); //  3 bits for picture_mux_order
 222                                                                 $info['mpeg']['video']['raw']['picture_mux_factor']                     = self::readBitsFromStream($bitstream, $bitstreamoffset,  3); //  3 bits for picture_mux_factor
 223                                                         }
 224
 225                                                         $info['mpeg']['video']['scalable_mode'] = self::scalableModeTextLookup($info['mpeg']['video']['raw']['scalable_mode']);
 226                                                         break;
 227
 228                                                 case  7: // 0111 Picture Display Extension ID
 229                                                         break;
 230
 231                                                 case  8: // 1000 Picture Coding Extension ID
 232                                                         $info['mpeg']['video']['raw']['f_code_00']                       = self::readBitsFromStream($bitstream, $bitstreamoffset,  4); // 4 bits for f_code[0][0] (forward horizontal)
 233                                                         $info['mpeg']['video']['raw']['f_code_01']                       = self::readBitsFromStream($bitstream, $bitstreamoffset,  4); // 4 bits for f_code[0][1] (forward vertical)
 234                                                         $info['mpeg']['video']['raw']['f_code_10']                       = self::readBitsFromStream($bitstream, $bitstreamoffset,  4); // 4 bits for f_code[1][0] (backward horizontal)
 235                                                         $info['mpeg']['video']['raw']['f_code_11']                       = self::readBitsFromStream($bitstream, $bitstreamoffset,  4); // 4 bits for f_code[1][1] (backward vertical)
 236                                                         $info['mpeg']['video']['raw']['intra_dc_precision']              = self::readBitsFromStream($bitstream, $bitstreamoffset,  2); // 2 bits for intra_dc_precision
 237                                                         $info['mpeg']['video']['raw']['picture_structure']               = self::readBitsFromStream($bitstream, $bitstreamoffset,  2); // 2 bits for picture_structure
 238                                                         $info['mpeg']['video']['raw']['top_field_first']                 = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); // 1 bit flag: top_field_first
 239                                                         $info['mpeg']['video']['raw']['frame_pred_frame_dct']            = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); // 1 bit flag: frame_pred_frame_dct
 240                                                         $info['mpeg']['video']['raw']['concealment_motion_vectors']      = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); // 1 bit flag: concealment_motion_vectors
 241                                                         $info['mpeg']['video']['raw']['q_scale_type']                    = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); // 1 bit flag: q_scale_type
 242                                                         $info['mpeg']['video']['raw']['intra_vlc_format']                = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); // 1 bit flag: intra_vlc_format
 243                                                         $info['mpeg']['video']['raw']['alternate_scan']                  = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); // 1 bit flag: alternate_scan
 244                                                         $info['mpeg']['video']['raw']['repeat_first_field']              = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); // 1 bit flag: repeat_first_field
 245                                                         $info['mpeg']['video']['raw']['chroma_420_type']                 = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); // 1 bit flag: chroma_420_type
 246                                                         $info['mpeg']['video']['raw']['progressive_frame']               = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); // 1 bit flag: progressive_frame
 247                                                         $info['mpeg']['video']['raw']['composite_display_flag']          = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); // 1 bit flag: composite_display_flag
 248                                                         if ($info['mpeg']['video']['raw']['composite_display_flag']) {
 249                                                                 $info['mpeg']['video']['raw']['v_axis']                      = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); // 1 bit flag: v_axis
 250                                                                 $info['mpeg']['video']['raw']['field_sequence']              = self::readBitsFromStream($bitstream, $bitstreamoffset,  3); // 3 bits for field_sequence
 251                                                                 $info['mpeg']['video']['raw']['sub_carrier']                 = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); // 1 bit flag: sub_carrier
 252                                                                 $info['mpeg']['video']['raw']['burst_amplitude']             = self::readBitsFromStream($bitstream, $bitstreamoffset,  7); // 7 bits for burst_amplitude
 253                                                                 $info['mpeg']['video']['raw']['sub_carrier_phase']           = self::readBitsFromStream($bitstream, $bitstreamoffset,  8); // 8 bits for sub_carrier_phase
 254                                                         }
 255
 256                                                         $info['mpeg']['video']['intra_dc_precision_bits'] = $info['mpeg']['video']['raw']['intra_dc_precision'] + 8;
 257                                                         $info['mpeg']['video']['picture_structure'] = self::pictureStructureTextLookup($info['mpeg']['video']['raw']['picture_structure']);
 258                                                         break;
 259
 260                                                 case  9: // 1001 Picture Spatial Scalable Extension ID
 261                                                         break;
 262                                                 case 10: // 1010 Picture Temporal Scalable Extension ID
 263                                                         break;
 264
 265                                                 default:
 266                                                         $this->warning('Unexpected $info[mpeg][video][raw][extension_start_code_identifier] value of '.$info['mpeg']['video']['raw']['extension_start_code_identifier']);
 267                                                         break;
 268                                         }
 269                                         break;
 270
 271
 272                                 case 0xB8: // group_of_pictures_header
 273                                         $GOPcounter++;
 274                                         if (!empty($info['mpeg']['video']['bitrate_mode']) && ($info['mpeg']['video']['bitrate_mode'] == 'vbr')) {
 275                                                 $bitstream = getid3_lib::BigEndian2Bin(substr($MPEGstreamData, $StartCodeOffset + 4, 4)); // 27 bits needed for group_of_pictures_header
 276                                                 $bitstreamoffset = 0;
 277
 278                                                 $GOPheader = array();
 279
 280                                                 $GOPheader['byte_offset'] = $MPEGstreamBaseOffset + $StartCodeOffset;
 281                                                 $GOPheader['drop_frame_flag']    = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: drop_frame_flag
 282                                                 $GOPheader['time_code_hours']    = self::readBitsFromStream($bitstream, $bitstreamoffset,  5); //  5 bits for time_code_hours
 283                                                 $GOPheader['time_code_minutes']  = self::readBitsFromStream($bitstream, $bitstreamoffset,  6); //  6 bits for time_code_minutes
 284                                                 $marker_bit                      = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); // The term "marker_bit" indicates a one bit field in which the value zero is forbidden. These marker bits are introduced at several points in the syntax to avoid start code emulation.
 285                                                 $GOPheader['time_code_seconds']  = self::readBitsFromStream($bitstream, $bitstreamoffset,  6); //  6 bits for time_code_seconds
 286                                                 $GOPheader['time_code_pictures'] = self::readBitsFromStream($bitstream, $bitstreamoffset,  6); //  6 bits for time_code_pictures
 287                                                 $GOPheader['closed_gop']         = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: closed_gop
 288                                                 $GOPheader['broken_link']        = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: broken_link
 289
 290                                                 $time_code_separator = ($GOPheader['drop_frame_flag'] ? ';' : ':'); // While non-drop time code is displayed with colons separating the digit pairs "HH:MM:SS:FF" drop frame is usually represented with a semi-colon (;) or period (.) as the divider between all the digit pairs "HH;MM;SS;FF", "HH.MM.SS.FF"
 291                                                 $GOPheader['time_code'] = sprintf('%02d'.$time_code_separator.'%02d'.$time_code_separator.'%02d'.$time_code_separator.'%02d', $GOPheader['time_code_hours'], $GOPheader['time_code_minutes'], $GOPheader['time_code_seconds'], $GOPheader['time_code_pictures']);
 292
 293                                                 $info['mpeg']['group_of_pictures'][] = $GOPheader;
 294                                         }
 295                                         break;
 296
 297                                 case 0xC0: // audio stream
 298                                 case 0xC1: // audio stream
 299                                 case 0xC2: // audio stream
 300                                 case 0xC3: // audio stream
 301                                 case 0xC4: // audio stream
 302                                 case 0xC5: // audio stream
 303                                 case 0xC6: // audio stream
 304                                 case 0xC7: // audio stream
 305                                 case 0xC8: // audio stream
 306                                 case 0xC9: // audio stream
 307                                 case 0xCA: // audio stream
 308                                 case 0xCB: // audio stream
 309                                 case 0xCC: // audio stream
 310                                 case 0xCD: // audio stream
 311                                 case 0xCE: // audio stream
 312                                 case 0xCF: // audio stream
 313                                 case 0xD0: // audio stream
 314                                 case 0xD1: // audio stream
 315                                 case 0xD2: // audio stream
 316                                 case 0xD3: // audio stream
 317                                 case 0xD4: // audio stream
 318                                 case 0xD5: // audio stream
 319                                 case 0xD6: // audio stream
 320                                 case 0xD7: // audio stream
 321                                 case 0xD8: // audio stream
 322                                 case 0xD9: // audio stream
 323                                 case 0xDA: // audio stream
 324                                 case 0xDB: // audio stream
 325                                 case 0xDC: // audio stream
 326                                 case 0xDD: // audio stream
 327                                 case 0xDE: // audio stream
 328                                 case 0xDF: // audio stream
 329                                 //case 0xE0: // video stream
 330                                 //case 0xE1: // video stream
 331                                 //case 0xE2: // video stream
 332                                 //case 0xE3: // video stream
 333                                 //case 0xE4: // video stream
 334                                 //case 0xE5: // video stream
 335                                 //case 0xE6: // video stream
 336                                 //case 0xE7: // video stream
 337                                 //case 0xE8: // video stream
 338                                 //case 0xE9: // video stream
 339                                 //case 0xEA: // video stream
 340                                 //case 0xEB: // video stream
 341                                 //case 0xEC: // video stream
 342                                 //case 0xED: // video stream
 343                                 //case 0xEE: // video stream
 344                                 //case 0xEF: // video stream
 345                                         if (isset($ParsedAVchannels[$StartCodeValue])) {
 346                                                 break;
 347                                         }
 348                                         $ParsedAVchannels[$StartCodeValue] = $StartCodeValue;
 349                                         // http://en.wikipedia.org/wiki/Packetized_elementary_stream
 350                                         // http://dvd.sourceforge.net/dvdinfo/pes-hdr.html
 351 /*
 352                                         $PackedElementaryStream = array();
 353                                         if ($StartCodeValue >= 0xE0) {
 354                                                 $PackedElementaryStream['stream_type'] = 'video';
 355                                                 $PackedElementaryStream['stream_id']   = $StartCodeValue - 0xE0;
 356                                         } else {
 357                                                 $PackedElementaryStream['stream_type'] = 'audio';
 358                                                 $PackedElementaryStream['stream_id']   = $StartCodeValue - 0xC0;
 359                                         }
 360                                         $PackedElementaryStream['packet_length'] = getid3_lib::BigEndian2Int(substr($MPEGstreamData, $StartCodeOffset + 4, 2));
 361
 362                                         $bitstream = getid3_lib::BigEndian2Bin(substr($MPEGstreamData, $StartCodeOffset + 6, 3)); // more may be needed below
 363                                         $bitstreamoffset = 0;
 364
 365                                         $PackedElementaryStream['marker_bits']               = self::readBitsFromStream($bitstream, $bitstreamoffset,  2); //  2 bits for marker_bits -- should be "10" = 2
 366 echo 'marker_bits = '.$PackedElementaryStream['marker_bits'].'<br>';
 367                                         $PackedElementaryStream['scrambling_control']        = self::readBitsFromStream($bitstream, $bitstreamoffset,  2); //  2 bits for scrambling_control -- 00 implies not scrambled
 368                                         $PackedElementaryStream['priority']                  = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: priority
 369                                         $PackedElementaryStream['data_alignment_indicator']  = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: data_alignment_indicator -- 1 indicates that the PES packet header is immediately followed by the video start code or audio syncword
 370                                         $PackedElementaryStream['copyright']                 = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: copyright -- 1 implies copyrighted
 371                                         $PackedElementaryStream['original_or_copy']          = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: original_or_copy -- 1 implies original
 372                                         $PackedElementaryStream['pts_flag']                  = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: pts_flag -- Presentation Time Stamp
 373                                         $PackedElementaryStream['dts_flag']                  = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: dts_flag -- Decode Time Stamp
 374                                         $PackedElementaryStream['escr_flag']                 = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: escr_flag -- Elementary Stream Clock Reference
 375                                         $PackedElementaryStream['es_rate_flag']              = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: es_rate_flag -- Elementary Stream [data] Rate
 376                                         $PackedElementaryStream['dsm_trick_mode_flag']       = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: dsm_trick_mode_flag -- DSM trick mode - not used by DVD
 377                                         $PackedElementaryStream['additional_copy_info_flag'] = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: additional_copy_info_flag
 378                                         $PackedElementaryStream['crc_flag']                  = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: crc_flag
 379                                         $PackedElementaryStream['extension_flag']            = self::readBitsFromStream($bitstream, $bitstreamoffset,  1); //  1 bit flag: extension_flag
 380                                         $PackedElementaryStream['pes_remain_header_length']  = self::readBitsFromStream($bitstream, $bitstreamoffset,  8); //  1 bit flag: priority
 381
 382                                         $additional_header_bytes = 0;
 383                                         $additional_header_bytes += ($PackedElementaryStream['pts_flag']                  ? 5 : 0);
 384                                         $additional_header_bytes += ($PackedElementaryStream['dts_flag']                  ? 5 : 0);
 385                                         $additional_header_bytes += ($PackedElementaryStream['escr_flag']                 ? 6 : 0);
 386                                         $additional_header_bytes += ($PackedElementaryStream['es_rate_flag']              ? 3 : 0);
 387                                         $additional_header_bytes += ($PackedElementaryStream['additional_copy_info_flag'] ? 1 : 0);
 388                                         $additional_header_bytes += ($PackedElementaryStream['crc_flag']                  ? 2 : 0);
 389                                         $additional_header_bytes += ($PackedElementaryStream['extension_flag']            ? 1 : 0);
 390 $PackedElementaryStream['additional_header_bytes'] = $additional_header_bytes;
 391                                         $bitstream .= getid3_lib::BigEndian2Bin(substr($MPEGstreamData, $StartCodeOffset + 9, $additional_header_bytes));
 392
 393                                         $info['mpeg']['packed_elementary_streams'][$PackedElementaryStream['stream_type']][$PackedElementaryStream['stream_id']][] = $PackedElementaryStream;
 394 */
 395                                         $getid3_temp = new getID3();
 396                                         $getid3_temp->openfile($this->getid3->filename);
 397                                         $getid3_temp->info = $info;
 398                                         $getid3_mp3 = new getid3_mp3($getid3_temp);
 399                                         for ($i = 0; $i <= 7; $i++) {
 400                                                 // some files have the MPEG-audio header 8 bytes after the end of the $00 $00 $01 $C0 signature, some have it up to 13 bytes (or more?) after
 401                                                 // I have no idea why or what the difference is, so this is a stupid hack.
 402                                                 // If anybody has any better idea of what's going on, please let me know - info@getid3.org
 403                                                 $getid3_temp->info = $info; // only overwrite real data if valid header found
 404 //echo 'audio at? '.($MPEGstreamBaseOffset + $StartCodeOffset + 4 + 8 + $i).'<br>';
 405                                                 if ($getid3_mp3->decodeMPEGaudioHeader($MPEGstreamBaseOffset + $StartCodeOffset + 4 + 8 + $i, $getid3_temp->info, false)) {
 406 //echo 'yes!<br>';
 407                                                         $info = $getid3_temp->info;
 408                                                         $info['audio']['bitrate_mode'] = 'cbr';
 409                                                         $info['audio']['lossless']     = false;
 410                                                         break;
 411                                                 }
 412                                         }
 413                                         unset($getid3_temp, $getid3_mp3);
 414                                         break;
 415
 416                                 case 0xBC: // Program Stream Map
 417                                 case 0xBD: // Private stream 1 (non MPEG audio, subpictures)
 418                                 case 0xBE: // Padding stream
 419                                 case 0xBF: // Private stream 2 (navigation data)
 420                                 case 0xF0: // ECM stream
 421                                 case 0xF1: // EMM stream
 422                                 case 0xF2: // DSM-CC stream
 423                                 case 0xF3: // ISO/IEC_13522_stream
 424                                 case 0xF4: // ITU-I Rec. H.222.1 type A
 425                                 case 0xF5: // ITU-I Rec. H.222.1 type B
 426                                 case 0xF6: // ITU-I Rec. H.222.1 type C
 427                                 case 0xF7: // ITU-I Rec. H.222.1 type D
 428                                 case 0xF8: // ITU-I Rec. H.222.1 type E
 429                                 case 0xF9: // ancilliary stream
 430                                 case 0xFA: // ISO/IEC 14496-1 SL-packtized stream
 431                                 case 0xFB: // ISO/IEC 14496-1 FlexMux stream
 432                                 case 0xFC: // metadata stream
 433                                 case 0xFD: // extended stream ID
 434                                 case 0xFE: // reserved data stream
 435                                 case 0xFF: // program stream directory
 436                                         // ignore
 437                                         break;
 438
 439                                 default:
 440                                         // ignore
 441                                         break;
 442                         }
 443                 } while (true);
 444
 445
 446
 447 //              // Temporary hack to account for interleaving overhead:
 448 //              if (!empty($info['video']['bitrate']) && !empty($info['audio']['bitrate'])) {
 449 //                      $info['playtime_seconds'] = (($info['avdataend'] - $info['avdataoffset']) * 8) / ($info['video']['bitrate'] + $info['audio']['bitrate']);
 450 //
 451 //                      // Interleaved MPEG audio/video files have a certain amount of overhead that varies
 452 //                      // by both video and audio bitrates, and not in any sensible, linear/logarithmic pattern
 453 //                      // Use interpolated lookup tables to approximately guess how much is overhead, because
 454 //                      // playtime is calculated as filesize / total-bitrate
 455 //                      $info['playtime_seconds'] *= self::systemNonOverheadPercentage($info['video']['bitrate'], $info['audio']['bitrate']);
 456 //
 457 //                      //switch ($info['video']['bitrate']) {
 458 //                      //      case('5000000'):
 459 //                      //              $multiplier = 0.93292642112380355828048824319889;
 460 //                      //              break;
 461 //                      //      case('5500000'):
 462 //                      //              $multiplier = 0.93582895375200989965359777343219;
 463 //                      //              break;
 464 //                      //      case('6000000'):
 465 //                      //              $multiplier = 0.93796247714820932532911373859139;
 466 //                      //              break;
 467 //                      //      case('7000000'):
 468 //                      //              $multiplier = 0.9413264083635103463010117778776;
 469 //                      //              break;
 470 //                      //      default:
 471 //                      //              $multiplier = 1;
 472 //                      //              break;
 473 //                      //}
 474 //                      //$info['playtime_seconds'] *= $multiplier;
 475 //                      //$this->warning('Interleaved MPEG audio/video playtime may be inaccurate. With current hack should be within a few seconds of accurate. Report to info@getid3.org if off by more than 10 seconds.');
 476 //                      if ($info['video']['bitrate'] < 50000) {
 477 //                              $this->warning('Interleaved MPEG audio/video playtime may be slightly inaccurate for video bitrates below 100kbps. Except in extreme low-bitrate situations, error should be less than 1%. Report to info@getid3.org if greater than this.');
 478 //                      }
 479 //              }
 480 //
 481 /*
 482 $time_prev = 0;
 483 $byte_prev = 0;
 484 $vbr_bitrates = array();
 485 foreach ($info['mpeg']['group_of_pictures'] as $gopkey => $gopdata) {
 486         $time_this = ($gopdata['time_code_hours'] * 3600) + ($gopdata['time_code_minutes'] * 60) + $gopdata['time_code_seconds'] + ($gopdata['time_code_seconds'] / 30);
 487         $byte_this = $gopdata['byte_offset'];
 488         if ($gopkey > 0) {
 489                 if ($time_this > $time_prev) {
 490                         $bytedelta = $byte_this - $byte_prev;
 491                         $timedelta = $time_this - $time_prev;
 492                         $this_bitrate = ($bytedelta * 8) / $timedelta;
 493 echo $gopkey.': ('.number_format($time_prev, 2).'-'.number_format($time_this, 2).') '.number_format($bytedelta).' bytes over '.number_format($timedelta, 3).' seconds = '.number_format($this_bitrate / 1000, 2).'kbps<br>';
 494                         $time_prev = $time_this;
 495                         $byte_prev = $byte_this;
 496                         $vbr_bitrates[] = $this_bitrate;
 497                 }
 498         }
 499 }
 500 echo 'average_File_bitrate = '.number_format(array_sum($vbr_bitrates) / count($vbr_bitrates), 1).'<br>';
 501 */
 502 //echo '<pre>'.print_r($FramesByGOP, true).'</pre>';
 503                 if (!empty($info['mpeg']['video']['bitrate_mode']) && ($info['mpeg']['video']['bitrate_mode'] == 'vbr')) {
 504                         $last_GOP_id = max(array_keys($FramesByGOP));
 505                         $frames_in_last_GOP = count($FramesByGOP[$last_GOP_id]);
 506                         $gopdata = &$info['mpeg']['group_of_pictures'][$last_GOP_id];
 507                         $info['playtime_seconds'] = ($gopdata['time_code_hours'] * 3600) + ($gopdata['time_code_minutes'] * 60) + $gopdata['time_code_seconds'] + (($gopdata['time_code_pictures'] + $frames_in_last_GOP + 1) / $info['mpeg']['video']['frame_rate']);
 508                         if (!isset($info['video']['bitrate'])) {
 509                                 $overall_bitrate = ($info['avdataend'] - $info['avdataoffset']) * 8 / $info['playtime_seconds'];
 510                                 $info['video']['bitrate'] = $overall_bitrate - (isset($info['audio']['bitrate']) ? $info['audio']['bitrate'] : 0);
 511                         }
 512                         unset($info['mpeg']['group_of_pictures']);
 513                 }
 514
 515                 return true;
 516         }
 517
 518         /**
 519          * @param string $bitstream
 520          * @param int    $bitstreamoffset
 521          * @param int    $bits_to_read
 522          * @param bool $return_singlebit_as_boolean
 523          *
 524          * @return bool|float|int
 525          */
 526         private function readBitsFromStream(&$bitstream, &$bitstreamoffset, $bits_to_read, $return_singlebit_as_boolean=true) {
 527                 $return = bindec(substr($bitstream, $bitstreamoffset, $bits_to_read));
 528                 $bitstreamoffset += $bits_to_read;
 529                 if (($bits_to_read == 1) && $return_singlebit_as_boolean) {
 530                         $return = (bool) $return;
 531                 }
 532                 return $return;
 533         }
 534
 535         /**
 536          * @param int $VideoBitrate
 537          * @param int $AudioBitrate
 538          *
 539          * @return float|int
 540          */
 541         public static function systemNonOverheadPercentage($VideoBitrate, $AudioBitrate) {
 542                 $OverheadPercentage = 0;
 543
 544                 $AudioBitrate = max(min($AudioBitrate / 1000,   384), 32); // limit to range of 32kbps - 384kbps (should be only legal bitrates, but maybe VBR?)
 545                 $VideoBitrate = max(min($VideoBitrate / 1000, 10000), 10); // limit to range of 10kbps -  10Mbps (beyond that curves flatten anyways, no big loss)
 546
 547
 548                 //OMBB[audiobitrate]              = array(video-10kbps,       video-100kbps,      video-1000kbps,     video-10000kbps)
 549                 $OverheadMultiplierByBitrate[32]  = array(0, 0.9676287944368530, 0.9802276264360310, 0.9844916183244460, 0.9852821845179940);
 550                 $OverheadMultiplierByBitrate[48]  = array(0, 0.9779100089209830, 0.9787770035359320, 0.9846738664076130, 0.9852683013799960);
 551                 $OverheadMultiplierByBitrate[56]  = array(0, 0.9731249855367600, 0.9776624308938040, 0.9832606361852130, 0.9843922606633340);
 552                 $OverheadMultiplierByBitrate[64]  = array(0, 0.9755642683275760, 0.9795256705493390, 0.9836573009193170, 0.9851122539404470);
 553                 $OverheadMultiplierByBitrate[96]  = array(0, 0.9788025247497290, 0.9798553314148700, 0.9822956869792560, 0.9834815119124690);
 554                 $OverheadMultiplierByBitrate[128] = array(0, 0.9816940050925480, 0.9821675936072120, 0.9829756927470870, 0.9839763420152050);
 555                 $OverheadMultiplierByBitrate[160] = array(0, 0.9825894094561180, 0.9820913399073960, 0.9823907143253970, 0.9832821783651570);
 556                 $OverheadMultiplierByBitrate[192] = array(0, 0.9832038474336260, 0.9825731694317960, 0.9821028622712400, 0.9828262076447620);
 557                 $OverheadMultiplierByBitrate[224] = array(0, 0.9836516298538770, 0.9824718601823890, 0.9818302180625380, 0.9823735101626480);
 558                 $OverheadMultiplierByBitrate[256] = array(0, 0.9845863022094920, 0.9837229411967540, 0.9824521662210830, 0.9828645172100790);
 559                 $OverheadMultiplierByBitrate[320] = array(0, 0.9849565280263180, 0.9837683142805110, 0.9822885275960400, 0.9824424382727190);
 560                 $OverheadMultiplierByBitrate[384] = array(0, 0.9856094774357600, 0.9844573394432720, 0.9825970399837330, 0.9824673808303890);
 561
 562                 $BitrateToUseMin = 32;
 563                 $BitrateToUseMax = 32;
 564                 $previousBitrate = 32;
 565                 foreach ($OverheadMultiplierByBitrate as $key => $value) {
 566                         if ($AudioBitrate >= $previousBitrate) {
 567                                 $BitrateToUseMin = $previousBitrate;
 568                         }
 569                         if ($AudioBitrate < $key) {
 570                                 $BitrateToUseMax = $key;
 571                                 break;
 572                         }
 573                         $previousBitrate = $key;
 574                 }
 575                 $FactorA = ($BitrateToUseMax - $AudioBitrate) / ($BitrateToUseMax - $BitrateToUseMin);
 576
 577                 $VideoBitrateLog10 = log10($VideoBitrate);
 578                 $VideoFactorMin1 = $OverheadMultiplierByBitrate[$BitrateToUseMin][floor($VideoBitrateLog10)];
 579                 $VideoFactorMin2 = $OverheadMultiplierByBitrate[$BitrateToUseMax][floor($VideoBitrateLog10)];
 580                 $VideoFactorMax1 = $OverheadMultiplierByBitrate[$BitrateToUseMin][ceil($VideoBitrateLog10)];
 581                 $VideoFactorMax2 = $OverheadMultiplierByBitrate[$BitrateToUseMax][ceil($VideoBitrateLog10)];
 582                 $FactorV = $VideoBitrateLog10 - floor($VideoBitrateLog10);
 583
 584                 $OverheadPercentage  = $VideoFactorMin1 *      $FactorA  *      $FactorV;
 585                 $OverheadPercentage += $VideoFactorMin2 * (1 - $FactorA) *      $FactorV;
 586                 $OverheadPercentage += $VideoFactorMax1 *      $FactorA  * (1 - $FactorV);
 587                 $OverheadPercentage += $VideoFactorMax2 * (1 - $FactorA) * (1 - $FactorV);
 588
 589                 return $OverheadPercentage;
 590         }
 591
 592         /**
 593          * @param int $rawframerate
 594          *
 595          * @return float
 596          */
 597         public static function videoFramerateLookup($rawframerate) {
 598                 $lookup = array(0, 23.976, 24, 25, 29.97, 30, 50, 59.94, 60);
 599                 return (float) (isset($lookup[$rawframerate]) ? $lookup[$rawframerate] : 0);
 600         }
 601
 602         /**
 603          * @param int $rawaspectratio
 604          * @param int $mpeg_version
 605          * @param int $width
 606          * @param int $height
 607          *
 608          * @return float
 609          */
 610         public static function videoAspectRatioLookup($rawaspectratio, $mpeg_version=1, $width=0, $height=0) {
 611                 $lookup = array(
 612                         1 => array(0, 1, 0.6735, 0.7031, 0.7615, 0.8055, 0.8437, 0.8935, 0.9157, 0.9815, 1.0255, 1.0695, 1.0950, 1.1575, 1.2015, 0),
 613                         2 => array(0, 1, 1.3333, 1.7778, 2.2100, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),
 614                 );
 615                 $ratio = (float) (isset($lookup[$mpeg_version][$rawaspectratio]) ? $lookup[$mpeg_version][$rawaspectratio] : 0);
 616                 if ($mpeg_version == 2 && $ratio != 1) {
 617                         // Calculate pixel aspect ratio from MPEG-2 display aspect ratio
 618                         $ratio = $ratio * $height / $width;
 619                 }
 620                 return $ratio;
 621         }
 622
 623         /**
 624          * @param int $rawaspectratio
 625      * @param int $mpeg_version
 626          *
 627          * @return string
 628          */
 629         public static function videoAspectRatioTextLookup($rawaspectratio, $mpeg_version=1) {
 630                 $lookup = array(
 631                         1 => array('forbidden', 'square pixels', '0.6735', '16:9, 625 line, PAL', '0.7615', '0.8055', '16:9, 525 line, NTSC', '0.8935', '4:3, 625 line, PAL, CCIR601', '0.9815', '1.0255', '1.0695', '4:3, 525 line, NTSC, CCIR601', '1.1575', '1.2015', 'reserved'),
 632                         2 => array('forbidden', 'square pixels', '4:3', '16:9', '2.21:1', 'reserved', 'reserved', 'reserved', 'reserved', 'reserved', 'reserved', 'reserved', 'reserved', 'reserved', 'reserved', 'reserved'), // http://dvd.sourceforge.net/dvdinfo/mpeghdrs.html
 633                 );
 634                 return (isset($lookup[$mpeg_version][$rawaspectratio]) ? $lookup[$mpeg_version][$rawaspectratio] : '');
 635         }
 636
 637         /**
 638          * @param int $video_format
 639          *
 640          * @return string
 641          */
 642         public static function videoFormatTextLookup($video_format) {
 643                 // ISO/IEC 13818-2, section 6.3.6, Table 6-6. Meaning of video_format
 644                 $lookup = array('component', 'PAL', 'NTSC', 'SECAM', 'MAC', 'Unspecified video format', 'reserved(6)', 'reserved(7)');
 645                 return (isset($lookup[$video_format]) ? $lookup[$video_format] : '');
 646         }
 647
 648         /**
 649          * @param int $scalable_mode
 650          *
 651          * @return string
 652          */
 653         public static function scalableModeTextLookup($scalable_mode) {
 654                 // ISO/IEC 13818-2, section 6.3.8, Table 6-10. Definition of scalable_mode
 655                 $lookup = array('data partitioning', 'spatial scalability', 'SNR scalability', 'temporal scalability');
 656                 return (isset($lookup[$scalable_mode]) ? $lookup[$scalable_mode] : '');
 657         }
 658
 659         /**
 660          * @param int $picture_structure
 661          *
 662          * @return string
 663          */
 664         public static function pictureStructureTextLookup($picture_structure) {
 665                 // ISO/IEC 13818-2, section 6.3.11, Table 6-14 Meaning of picture_structure
 666                 $lookup = array('reserved', 'Top Field', 'Bottom Field', 'Frame picture');
 667                 return (isset($lookup[$picture_structure]) ? $lookup[$picture_structure] : '');
 668         }
 669
 670         /**
 671          * @param int $chroma_format
 672          *
 673          * @return string
 674          */
 675         public static function chromaFormatTextLookup($chroma_format) {
 676                 // ISO/IEC 13818-2, section 6.3.11, Table 6-14 Meaning of picture_structure
 677                 $lookup = array('reserved', '4:2:0', '4:2:2', '4:4:4');
 678                 return (isset($lookup[$chroma_format]) ? $lookup[$chroma_format] : '');
 679         }
 680
 681 }