CODEWITHSUNDEEP
video-processingvideo-encodinglibavlibavcodeclibavformat
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Reputation: 43

Cannot mux video with libav: Tag avc1 incompatible with output codec id '27'

When I try to convert mp4 to flv, I get this error:

Tag avc1 incompatible with output codec id '27'

Codec 27 is AV_CODEC_ID_H264

I followed the examples from the documentation, and could write an image from mp4, or remux the file using the same encoders. https://github.com/FFmpeg/FFmpeg/blob/master/doc/examples/muxing.c

AVCodec* video_codec = NULL;
// It loops through the streams and copy the parameters 
for (int i=0; I<ctx->nb_streams; i++) {
  if (ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
    video_codec = avcodec_find_decoder(stream->codepar->codec_id);
  }
}

...

const char* output_file = "output_video.flv"
// it works with mp4, not with flv
avformat_alloc_output_context2(&fmt_ctx, NULL, "flv", output_file);

...

// Error here
avformat_write_header(fmt_ctx, NULL);

Output #0, flv, to 'output_video.flv':
    Stream #0:0: Video: h264 (avc1 / 0x4), none, 1920x1080, q=2-31, 6664 kb/s
    Stream #0:1: Audio: aac (mp4a / 0x5), 48000 Hz, 2 channels, 128 kb/s
[flv @ 0x5] Tag avc1 incompatible with output codec id '27' ([7][0][0][0])

What does this error means and where is this tag defined? Why copying the parameters isn't enough?

Upvotes: 1

Views: 1891

Answers (1)

Dinesh Tamilselvan
Dinesh Tamilselvan

Reputation: 11

Set the codec_tag (out_stream->codecpar->codec_tag) as 0 or corresponding AVI FOURCC codec tag inside the for loop for each output stream.

Upvotes: 1

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