[FFmpeg-user] MPEG-TS PCR Accuracy over +-500ns

袁竞杰 yuanjingjie1987 at 126.com
Wed Nov 27 10:57:07 CET 2013

Here is the command:
ffmpeg -i input.ts -muxrate 1700k -aspect 4:3 -b:v 1400k -maxrate 1400k -minrate 1400k -bufsize 1400k -c:v h264 -refs 1  -x264opts  bitrate=1400:vbv-maxrate=1400:vbv-bufsize=750:nal_hrd=cbr:fps=25:force_cfr:b-pyramid=0  -s 1280x720 -profile:v high -level 41 -preset medium -c:a libfaac -ar 48000 -ab 48k -f mpegts   output.ts
stream analyzer shows  fluctuation percentage of bitrate  is below 2%.
Constant frame size?Do you mean constant frame rate?
I used x264 options to obain cbr before,when added "-minrate 1400k -maxrate 1400k -bufsize 1400",PCR accuracy become better.Can you explain this?
Now most of packets PCR accuracy is within +-500ns, but there are  still several  packets out of range.What  can I do to keep PCR jitter of all packets  within -+500ns?

At 2013-11-26 22:30:04,"Carl Eugen Hoyos" <cehoyos at ag.or.at> wrote:
>Massimo Battistel <battistel <at> gmail.com> writes:
>> with these settings (supposing mpeg2) "-b:v 2000k 
>> -minrate 2000k -maxrate 2000k -bufsize 2000k" ?
>> Is this cbr or constant frame size?
>I don't think constant frame size exists for MPEG2, 
>this probably defines CBR.
>Note that afaict, you need a stream analyzer to 
>verify that the result actually is CBR, it is not 
>something that you can "see" by just looking at 
>the stream.
>Carl Eugen
>ffmpeg-user mailing list
>ffmpeg-user at ffmpeg.org

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