Bug #86793 for MP3-Cut-Gapless: MP3::Cut::Gapless does not respect bitrate

Hi! Thanks for your work on this. BUG NAME: MP3::Cut::Gapless does not correctly respect bitrate PLATFORM * Perl: v5.8.8 built for i386-linux-thread-multi * OS: CentOS (like Fedora) * Linux 192.168.123.130 2.6.18-348.4.1.el5 #1 SMP Tue Apr 16 16:02:56 EDT 2013 i686 athlon i386 GNU/Linux * MP3::Cut::Gapless is up to date (0.03). PROBLEM: * When I cut an mp3 file, it does not respect the bitrate. * I think maybe the first frame is the only one that is screwed up as the streaming server complains about it and then assumes it is VBR encoding. * Trouble is that MP3Info reports the incorrect duration which is calculated based on the bitrate. * Maybe 64k is assumed?? EXAMPLE: Cut 32kpbs file (mono) that is nominally 3600 seconds long (an hour) into two 1800 sec segments. Info about the source file: ------------------------------------- print_mp3info($src_mp3_file, $sourcepath) dn2013-0705-1.mp3 MPEG VERSION 2 MPEG LAYER 3 STEREO VBR BITRATE 32 kbps FREQUENCY 22.05 KHz SIZE 14168294 bytes OFFSET 269 bytes SECS 3542.0735 MM minutes 59 SS seconds left 2 MS ms left 73.4999999999673 TIME in MM:SS 59:02 COPYRIGHT PADDING MODE 3 (single channel) FRAMES 135595 FRAME_LENGTH 104 VBR_SCALE ============================ AND here is the info about the output file after cutting off the first 1800 seconds: Notice that it is set to 64kpbs and it thinks the file is 900 seconds long. (when played it will play for 1800 seconds) Player thinks first frame is different from the rest. DB<6> print_mp3info($outname, $outdir.'/'.$outname) cut_dn2013-0705-1_1800_000.mp3 MPEG VERSION 2 MPEG LAYER 3 STEREO VBR BITRATE 64 kbps FREQUENCY 22.05 KHz SIZE 7200493 bytes OFFSET bytes SECS 900.061625 MM minutes 15 SS seconds left MS ms left 61.6250000000491 TIME in MM:SS 15:00 COPYRIGHT PADDING MODE 3 (single channel) FRAMES 34455 FRAME_LENGTH 208 VBR_SCALE ============================ Cutting algorithm my $cut = MP3::Cut::Gapless->new( file => $sourcepath, cache_dir => $Config{TempDir}, start_ms => 0, end_ms => 1800, ); open my $out, '>', $outdir.'/'.$outname; while ( $cut->read( my $buf, 4096 ) ) { syswrite $out, $buf; } close $out; You can check the input and output files I used to test this here: http://www.cognisys.com/downloads/MP3-Cut-Gapless-errorfiles Contact me at raylutz@cognisys.com -- ----------------------- Ray Lutz Cognisys, Inc. Cognisys.com 619-820-5321