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

belcampo belcampo
Mon Oct 19 15:49:26 CEST 2009


Niobos wrote:
> On 19 Oct 2009, at 10:46, belcampo wrote:
>> Niobos wrote:
>>> On 16 Oct 2009, at 16:56, belcampo wrote:
>>>> 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
>>> Is this a pure cosmetic problem? or is there a difference in the 
>>> output file?
>> No it's NOT cosmetic only. File-size, also in the real world, grows 
>> from Lsize= 3996695kB to
>> Lsize= 7371403kB
> 
> That points more "away" from the muxer: As far as I understand the 
> muxer-code, it only puts a header/trailer around the bytes it gets from 
> the rest of the code.
> 
> To confirm this guess, could you retry the same test but with another 
> codec (eg mpeg2)?
source.mpg incl. audio-track is 1911772564bytes
ffmpeg -i source.mpg -an -vcodec copy -f mpegts result.ts
result.ts is 2602941968bytes
-rw-r--r-- 1 root   root  1911772564 2009-10-19 04:50 
tv/29014_20091019041500.mpg
-rw-r--r-- 1 mythtv users 2602941968 2009-10-19 15:45 
tv/29014_20091019041500.ts
> 
> Greets,
> Niobos
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