On 4/20/18 2:20 AM, Ronak wrote: > Hi, > > I've been testing FFMPEG's HLS fragmented MP4 options with some M4A audio > files. > > I've noticed that if I ask ffmpeg to fragment an 11 minute file vs a 10 hour > file, the byte ranges are different, even if the channel count/sampling > rate/bit rate and codec are the same. > > Here's an example of what I'm talking about: > > #EXTM3U > #EXT-X-VERSION:6 > #EXT-X-TARGETDURATION:10 > #EXT-X-MEDIA-SEQUENCE:1 > #EXT-X-MAP:URI="someAudio.m4s",BYTERANGE="738@0" > #EXTINF:9.798821, > #EXT-X-BYTERANGE:38977@738 > someAudio.m4s > #EXTINF:9.798821, > #EXT-X-BYTERANGE:38735@39715 > someAudio.m4s > #EXTINF:9.798821, > #EXT-X-BYTERANGE:38650@78450 > someAudio.m4s > #EXTINF:9.798821, > #EXT-X-BYTERANGE:38688@117100 > someAudio.m4s > #EXTINF:9.798821, > #EXT-X-BYTERANGE:38820@155788 > someAudio.m4s > > And > > #EXTM3U > #EXT-X-VERSION:6 > #EXT-X-TARGETDURATION:10 > #EXT-X-MEDIA-SEQUENCE:1 > #EXT-X-MAP:URI="someOtherAudio.m4s",BYTERANGE="738@0" > #EXTINF:9.798821, > #EXT-X-BYTERANGE:38724@738 > someOtherAudio.m4s > #EXTINF:9.798821, > #EXT-X-BYTERANGE:38812@39462 > someOtherAudio.m4s > #EXTINF:9.798821, > #EXT-X-BYTERANGE:38632@78274 > someOtherAudio.m4s > #EXTINF:9.798821, > #EXT-X-BYTERANGE:38804@116906 > someOtherAudio.m4s > #EXTINF:9.798821, > #EXT-X-BYTERANGE:38720@155710 > someOtherAudio.m4s > > Why would these byte ranges be different? I've been trying to look through > the libavformat source code > (https://github.com/FFmpeg/FFmpeg/blob/master/libavformat/hlsenc.c > <https://github.com/FFmpeg/FFmpeg/blob/master/libavformat/hlsenc.c>) but it > looks like this determination is done in whoever calls hls_write_packet. Yes, you are right. It is determined by the AV encoder(say AAC encoder in your case). HLS segmenter will just cut at the segment boundaries and it doesn't worry about the number of bytes that are present in that segment. > > Thanks, > > Ronak > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
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