Question

I’ve got a c++ library that is encoding video in realtime from webcams to mp4 files (H264). The settings i’ve got are as follows:

    codecContex->profile=FF_PROFILE_H264_BASELINE; //Baseline
    codecContex->gop_size=250;
    codecContex->max_b_frames=0;
    codecContex->max_qdiff=4;
    codecContex->me_method=libffmpeg::ME_HEX;
    codecContex->me_range=16;
    codecContex->qmin=10;
    codecContex->qmax=51;
    codecContex->qcompress=0.6;
    codecContex->keyint_min=10;
    codecContex->trellis=0;
    codecContex->level=13; //Level 1.3
    codecContex->weighted_p_pred = 2;
    codecContex->flags2|=CODEC_FLAG2_WPRED+CODEC_FLAG2_8X8DCT;

This creates MP4 files that play on iOS devices and on Windows Phone 7 devices but not on Android devices. I’ve read that Android only supports movies encoded with the baseline profile. These settings should produce a baseline movie but when I look at the generated MP4 file with MediaInfo it says it’s AVC(High@L1.3). This might be why it’s not working but I can’t seem to get it to generate something with AVC(Baseline@L1.3)…

If I remove the last line:

codecContex->flags2|=CODEC_FLAG2_WPRED+CODEC_FLAG2_8X8DCT;

Then MediaInfo reports the file as being “AVC(Main@L1.3)” instead – but those flags are part of the Baseline profile!

Answer 1

I got it baseline encoding with the following options:

    codecContex->coder_type = 0;
    codecContex->flags|=CODEC_FLAG_LOOP_FILTER;
    codecContex->profile=FF_PROFILE_H264_BASELINE; //Baseline
    codecContex->scenechange_threshold = 40; 
    codecContex->gop_size=250;
    codecContex->max_b_frames=0;
    codecContex->max_qdiff=4;
    codecContex->me_method=7;
    codecContex->me_range=16;
    codecContex->me_cmp|= 1;
    codecContex->me_subpel_quality = 6; 
    codecContex->qmin=10;
    codecContex->qmax=51;
    codecContex->qcompress=0.6;
    codecContex->keyint_min=25;
    codecContex->trellis=0;
    codecContex->level=13; //Level 1.3
    codecContex->refs = 1;
    codecContex->weighted_p_pred = 0;
    codecContex->crf = 20.0f;
    codecContex->flags2|=CODEC_FLAG2_BPYRAMID-CODEC_FLAG2_WPRED-CODEC_FLAG2_8X8DCT;

… the video wont play in an HTML5 video element but will if you load the mp4 file directly in the browser. The movie must also be 480px or less in width.