[Libav-user] CodecContext Optimization to Decode H264

Jérôme SALAYET jerome.salayet at hymatom.fr
Thu Feb 21 12:25:40 CET 2013



I use the last released FFMPEG library to decode H264 video streams (each frame send to the avcodec_decode_video2 function is a full video frame).


When I look several code sources samples, it seems that everyone set differents options for the CodecContext and the Codec flags.


I someone can tell me if I use the better ones to decode H264 :


m_lpCodecCtx->skip_frame       =  AVDISCARD_NONREF;

m_lpCodecCtx->skip_loop_filter =  AVDISCARD_ALL;

m_lpCodecCtx->skip_idct        =  AVDISCARD_ALL;

m_lpCodecCtx->idct_algo        =  1;

m_lpCodecCtx->has_b_frames     =  0;

m_lpCodecCtx->refs             =  1;

av_opt_set(m_lpCodecCtx->priv_data, "preset", "ultrafast", 0);

av_opt_set(m_lpCodecCtx->priv_data, "tune", "zerolatency", 0);



I also set the codec flags like this :



 m_lpCodecCtx->flags|= CODEC_FLAG_TRUNCATED;

// Enable faster H264 decode.

m_lpCodec->capabilities |= CODEC_CAP_FRAME_THREADS;

m_lpCodecCtx->flags     |= CODEC_FLAG_LOW_DELAY;

m_lpCodecCtx->flags2    |= CODEC_FLAG2_FAST;




Ingénieur Informatique
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Email : jerome.salayet at hymatom.fr <mailto:jerome.salayet at hymatom.fr> 


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