[Libav-user] My attempt to transcode is writing only a single stream of a two streams output format

Leandro Moreira leandro.ribeiro.moreira at gmail.com
Mon Dec 4 02:39:23 EET 2017

I'm trying to code a simple transcoder, using the new API, that replicates
to the following command line:

ffmpeg -i input.mp4 -c:v libx264 -x264-params
keyint=60:min-keyint=60:no-scenecut=1 -c:a copy output.mp4

I followed the transcoding example on Doxygen documentation but using the
new API.

My attempt to code it didn't work, either I get a single audio stream on an
mp4, that works, or a video stream on an mp4 that doesn't work.

I don't see any error message, the messages I see are these:

[libx264 @ 0x7fd0ae038000] using SAR=1/1
[libx264 @ 0x7fd0ae038000] MB rate (489600000) > level limit (2073600)
[libx264 @ 0x7fd0ae038000] using cpu capabilities: MMX2 SSE2Fast SSSE3
[libx264 @ 0x7fd0ae038000] profile High, level 5.2

The whole file

Anyway, what I did was:

*I created a transcode context type:*

typedef struct TrancodeContext {
  char *file_name;
  AVFormatContext *format_context;
  int audio_stream_index;
  int video_stream_index;
  AVStream *stream[2];
  AVCodec *codec[2];
  AVCodecContext *codec_context[2];
} TranscodeContext;

*Prepared the decoder
with the functions:*

   1. avformat_alloc_context,
   2. avformat_open_input,
   3. avformat_find_stream_info,
   4. avcodec_find_decoder,
   5. avcodec_alloc_context3,
   6. avcodec_parameters_to_context,
   7. avcodec_open2

*Prepared the encoder
with the functions:*

   1. avformat_alloc_output_context2,
   2. avformat_new_stream,
   3. avcodec_find_encoder_by_name,
   4. avcodec_alloc_context3,
   5. avcodec_parameters_from_context,
   6. avcodec_find_encoder,
   7. avcodec_alloc_context3,
   8. avformat_new_stream,
   9. avcodec_open2,
   10. avcodec_parameters_from_context,
   11. avio_open,
   12. avformat_write_header

*Read all the packets:*

while (av_read_frame(decoder_context->format_context, input_packet) >= 0)

*Decode the video packets
into frames:*

   1. avcodec_send_packet,
   2. avcodec_receive_frame

*Encode the frame
into the encoder:*

   1. avcodec_send_frame,
   2. avcodec_receive_packet,
   3. av_packet_rescale_ts,
   4. av_interleaved_write_frame

*Copy audio stream directly
to the encoder:*

   1. av_packet_rescale_ts,
   2. av_interleaved_write_frame

*Finish with* av_write_trailer

Can you see anything suspicious on that? I tried really hard
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://ffmpeg.org/pipermail/libav-user/attachments/20171204/d628a14c/attachment.html>

More information about the Libav-user mailing list