[Libav-user] h264 encode speed

hz nan nhongzhen at gmail.com
Tue Jul 19 09:48:55 CEST 2011


Hi
I need to using H264 to live broadcast and it need 25 frames in one second.,
so I need to encode 25 frames
in one second. If the frame is 160*120 or 320*240 ,it is ok. But if it is
640*480, it need more than 70ms to
encode one frame. Does anyone have suggestion about how to increase encode
and decode speed?

Thanks  Hongzhen Nan

------------------------------------------

libx264 compile: ../configure ---enable-static --disable-lavf --disable-ffms
--disable-gpac --enable-win32thread --disable-swscale
ffmpeg compile:  ../configure --enable-static --enable-gpl --disable-mmx
--enable-libx264 --disable-ffmpeg --disable-ffmplay
 --disable-ffprobe --disable-ffserver --disable-postproc --enable-w32threads

H264 encode:
              pCodec = avcodec_find_encoder(CODEC_ID_H264);

        pCodecCtx= avcodec_alloc_context();

        pCodecCtx->width = v_width;

        pCodecCtx->height = v_height;

        pCodecCtx->pix_fmt = PIX_FMT_YUV420P;

        pCodecCtx->time_base.den = 1;

        pCodecCtx->time_base.num = 25;

        pCodecCtx->coder_type=FF_CODER_TYPE_AC;

        pCodecCtx->flags|=(CODEC_FLAG_LOOP_FILTER);

        pCodecCtx->me_cmp|=1;

        pCodecCtx->partitions|=(X264_PART_I8X8|X264_PART_I4X4|X264_PART_P8X8|X264_PART_B8X8);

        pCodecCtx->me_method=ME_HEX;

        pCodecCtx->me_subpel_quality=7;

        pCodecCtx->me_range=16;

        pCodecCtx->gop_size=20;

        pCodecCtx->scenechange_threshold=40;

        pCodecCtx->qcompress=0.6;

        pCodecCtx->qmin=10;

        pCodecCtx->qmax=51;

        pCodecCtx->max_qdiff=4;

        pCodecCtx->max_b_frames=3;

        pCodecCtx->refs=3;

        pCodecCtx->flags2
|=(CODEC_FLAG2_BPYRAMID|CODEC_FLAG2_MIXED_REFS|CODEC_FLAG2_WPRED|CODEC_FLAG2_8X8DCT|CODEC_FLAG2_FASTPSKIP);

        pCodecCtx->weighted_p_pred=2;

        pCodecCtx->rc_lookahead=0;

        pCodecCtx->crf=22;

        while(avcodec_open(pCodecCtx,pCodec)<0);
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