[Ffmpeg-devel] MPEGTS overhead is huge - is that normal?

[Andy Parkins]

Hello

I've just noticed the huge difference in file size when storing as MPEGTS 
compared to raw.  For example:

Output #0, m4v, to 'live.m4v':
  Stream #0.0: Video: mpeg4, 720x576, 25.00 fps, q=2-31, 20 kb/s
2005/06/22 11:23:43  Key frame; file size now 217440 = 54360 bytes/sec
2005/06/22 11:23:47  Key frame; file size now 431668 = 53958 bytes/sec
2005/06/22 11:23:51  Key frame; file size now 650788 = 54232 bytes/sec
2005/06/22 11:23:55  Key frame; file size now 861410 = 53838 bytes/sec
2005/06/22 11:23:59  Key frame; file size now 1074468 = 53723 bytes/sec
2005/06/22 11:24:03  Key frame; file size now 1292522 = 53855 bytes/sec
2005/06/22 11:24:07  Key frame; file size now 1507446 = 53837 bytes/sec
2005/06/22 11:24:11  Key frame; file size now 1729208 = 54037 bytes/sec
2005/06/22 11:24:15  Key frame; file size now 1947932 = 54109 bytes/sec
etc

and

Output #0, mpegts, to 'live.ts':
  Stream #0.0: Video: mpeg4, 720x576, 25.00 fps, q=2-31, 20 kb/s
2005/06/22 11:22:48  Key frame; file size now 739216 = 246405 bytes/sec
2005/06/22 11:22:52  Key frame; file size now 1478056 = 211150 bytes/sec
2005/06/22 11:22:56  Key frame; file size now 2206744 = 200613 bytes/sec
2005/06/22 11:23:00  Key frame; file size now 2945584 = 196372 bytes/sec
2005/06/22 11:23:04  Key frame; file size now 3674272 = 193382 bytes/sec
2005/06/22 11:23:08  Key frame; file size now 4433416 = 192757 bytes/sec

192kb/s compared to 54kb/s?  I could fit another three MPEG4 streams in the 
MPEGTS overhead.  Is that correct?  Is there some setting that needs tuning?


Andy

-- 
Dr Andrew Parkins, M Eng (hons), AMIEE

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