[FFmpeg-devel] [bug/patch] MPEG-TS muxer: PCR not in sync withPTS/DTS

[belcampo]

Alexandre Ferrieux wrote:
> (resending, not sure the intended dest got it ;-)
> 
> Hi Niobos,
> 
>> Niobos wrote:
>>>
>>> I reviewed this patch since I needed some additional features:
>>> * Bugfix: In VBR mode, the SI-table period was calculated on the 
>>> muxrate after it had been multiplied by 10. The resulting rates were 
>>> 10x to slow.
>>> * Extra feature: Specifying a negative muxrate on the commandline 
>>> overwrites the calculated muxrate, but still activates VBR.
>>> * I added an additional patch which includes some additional 
>>> info/clarification and does not cause any changes in the compiled code.
>>>
>>> This extra feature is needed to produce a VBR MPEG-TS by 
>>> remultiplexing a source ("-{a,v}codec copy"), since the bitrates 
>>> can't be learned from the stearm.
>>>
>>> Attached patches are against r20080.
> 
> 
> As usual I tested your update. Indeed the fix of the SI table frequency
> has a nice effect on hardware decoders :-)
> 
> Now I observed a regression wrt your previous patches: when muxing an
> audio-only TS, the PCR is wrong by a large factor (between 4 and 6 times
> too slow). When muxing video only or both, it is correct.
> 
> -Alex
> 
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Not to interfere, maybe off-topic, not intended anyway, I think it's 
relevant.

After applying the patch, ffmpeg-mpegts-vbr-4.diff, doing
ffmpeg -i 86240frames-h264.ts -an -vcodec copy -f rawvideo 
86240frames.h264  produces the raw frames where last line is:
frame=172480 fps=2285 q=-1.0 Lsize= 3996695kB time=3449.58 
bitrate=9491.3kbits/s

Notice frame vs. field problem.

ffmpeg -i 86240frames.h264 -an -vcodec copy -f mpegts new.ts
now produces
frame=172480 fps=1393 q=-1.0 Lsize= 7371403kB time=3449.62 
bitrate=17505.3kbits/s

Notice size/bitrate increase
FFmpeg version SVN-r20199, Copyright (c) 2000-2009 Fabrice Bellard, et al.
   built on Oct 16 2009 16:18:11 with gcc 4.2.2 20070909 (prerelease) 
(4.2.2-0.RC.1mdv2008.0)
   configuration: --prefix=/usr --enable-libx264 --enable-libxvid 
--enable-gpl --enable-libfaac --enable-libmp3lame --enable-pthreads 
--disable-ffserver --enable-libfaad --disable-ffplay --as=yasm 
--enable-nonfree
   libavutil     50. 3. 0 / 50. 3. 0
   libavcodec    52.36. 0 / 52.36. 0
   libavformat   52.39. 0 / 52.39. 0
   libavdevice   52. 2. 0 / 52. 2. 0
   libswscale     0. 7. 1 /  0. 7. 1