You can get a part of the audio track from MP4 video flexibly. You can use WidsMob Capture to record and extract audio from any MP4 video, including online and offline videos.Ĭompared with video to audio converters, the program can help you extract audio from MP4 without losing quality. Is it possible to download and extract audio from YouTube videos? Absolutely yes. Sometimes you need to extract audio from online streaming video sites, like YouTube, Vimeo, and more.

Start with the transcode_aac official example.Part 1: Lossless Way to Extract Audio from MP4 on Mac You can looking into demuxing.c and muxing.c provided in ffmpeg examples. You can use av_read_frame(informat, &pkt), avcodec_decode_audio4(in_aud_codec_ctx, pframeT, &got_vid_pkt, &pkt), avcodec_encode_audio2() and av_write_frame().įinally write trailer using av_write_trailer. Now in while loop start reading packet, decode only audio packet encode them and write them in opened output file. Write the output headers using avformat_write_header(outformat, NULL). Now for output file guess the outformat using av_guess_format(NULL, (const char*)outfile, NULL).įind output audio encoder using avcodec_find_encoder(outfmt->audio_codec).Īdd new stream audio stream avformat_new_stream(outformat, out_aud_codec).įill output codec context with desired sample rate, sample fmt, channel etc.

Use avcodec_find_decoder(in_aud_strm->codec->codec_id) and avcodec_open2(in_aud_codec_ctx, in_aud_codec, NULL).

Once you have input audio stream you can find audio decoder and open the decoder. Open input file using avformat_open_input( &informat, sourcefile, 0, 0)).įind stream info using avformat_find_stream_info(informat, 0)).įind the audio stream by iterating through streams and comparing codec_type to AVMEDIA_TYPE_AUDIO. You can try using ffmpeg to do it in C or C++.

Ffmpeg extract audio mp4