How to set x264 encode parameters through ffmpeg AVCodecContext

Question

I'm trying to use ffmpeg/libx264 to encode and transmit a realtime video, when I use **av_dict_set(&opts, "tune", "zerolatency", 0); ** the system works well. As the X264 encode parameters are set by ffmpeg using av_dict_set , for some research purpose I want to change them by myself. But some parameters in x264_param_t can not correspond to those parameters in AVCodecContext , such as vfr_input . So I want to know if there is a directly way to transmit parameters into X264 encoder when using libx264 in ffmpeg.

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Can anyone help me? Thanks

Answer 1

Try calling av_opt_set with the codec context priv_data structure:

AVCodec *codec = avcodec_find_encoder(AV_CODEC_ID_H264);
AVCodecContext *codecContex = avcodec_alloc_context3(codec);
av_opt_set(codecContex->priv_data, "preset", "ultrafast", 0);
av_opt_set(codecContex->priv_data, "tune", "zerolatency", 0);

Error checking omitted for brevity.