[Libav-user] Problem with using libavcodec with AV_CODEC_ID_H264

Alex Cohn alexcohn at netvision.net.il
Sat Feb 9 21:45:45 CET 2013


On Sat, Feb 9, 2013 at 10:24 PM, Ashwin Chandra - SISA
<ashwin.c at sisa.samsung.com> wrote:
> Can you tell me the exact options for the preset you mentioned. I want I and P frames and not B frames to reduce latency but gain better h264 compression rather than mpeg 2.
>
> On Feb 9, 2013, at 11:38 AM, "Alex Cohn" <alexcohn at netvision.net.il> wrote:
>
>> On Fri, Feb 8, 2013 at 8:21 PM, Ashwin Chandra - SISA
>> <ashwin.c at sisa.samsung.com> wrote:
>>> All those presets I tried but didn’t help.
>>
>> You should try the zerolatency preset, and not allow any b-frames if
>> you want to flush so often. You can try to set max gop size to 1. Even
>> in this case, h264 is not optimized for this kind of flushing. What
>> were the motivations of choosing this codec? JPEG should suit you
>> best.
>>
>> BR,
>> Alex

You could find the answer on this list:
http://libav-users.943685.n4.nabble.com/Libav-user-FFmpeg-x264-settings-for-zero-delay-encoding-tp4655209p4655212.html.

I don't think you can get a significant improvement without using
B-frames and requiring immediate flush, but it's up to you to test it
with your input and choose the optimal parameters.

Sincerely,
Alex


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