Newest 'ffmpeg' Questions - Stack Overflow

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• ffmpeg - alternative to AVCodecContext::refcounted_frames ?

  18 mars 2014, par Asik

  We are using an outdated version of AVCodec which does not contain the ref-counted frames feature implemented via AVCodecContext::refcounted_frames. Basically, we want to prevent AVCodec from re-using a buffer until we are done with it, which could be at any arbitrary point in the future (and not necessarily before the next avcodec_decode_frame2).

  Using a different AVFrame on each call to decode doesn't do the trick, because AVCodec uses the same buffers internally anyway (different AVFrames may point to the same data).

  Is there a way to do this without using the new features introduced with AVCodecContext::refcounted_frames?

• avconv much longer than ffmpeg

  18 mars 2014, par fsulser

  I was using ffmpeg to generate some images from a video. Now I read that I shouldn't use ffmpeg longer and use avconv from libav instead. So I tried to do the same thing with avconv.

  The ffmpeg is looking like this:

  ffmpeg -ss 1000 -t 5 -i 'test.mp4' -s '120*90' -r 10 out%2d.bmp
  

  Same with avconv:

  avconv -ss 1000 -t 5 -i 'test.mp4' -s '120*90' -r 10 out%2d.bmp
  

  ffmpeg needs less than one second to finish. Avconv about 90 seconds for the same task. Is this usual or do I need to change some things to work with avconv?

• Repeat/loop the video till audio file using ffmpeg

  18 mars 2014, par M. Usman Afzal

  I am using this command to generate the video from silent video and audio but the problem is video is 3 sec and audio is 20 sec and final video generating is 20 sec but video is for 3 sec and the last frame of that video is repeat till end.

  ffmpeg -i v.mp4 -i a.m4a -c:v copy -c:a aac -strict experimental -map 0:v:0 -map 1:a:0 output.mp4

  I just want to repeat the whole video

• How to use ffmpeg to mix two audio files to a single one ?

  18 mars 2014, par Dead Live

  I want to mix two audio files to a single one use ffmpeg. So I download the latest version of ffmpeg, and check the document and get the code:

  ffmpeg -i 10001.wav -i 201.wav -filter_complex amix=inputs=2:duration=shortest output.wav
  

  but I got this error:

  ffmpeg version 0.11.1 Copyright (c) 2000-2012 the FFmpeg developers
    built on Aug  9 2012 16:22:59 with gcc 4.1.2 20080704 (Red Hat 4.1.2-52)
    configuration: --prefix=/usr/ --enable-gpl --enable-libx264 --enable-libmp3lame
    libavutil      51. 54.100 / 51. 54.100
    libavcodec     54. 23.100 / 54. 23.100
    libavformat    54.  6.100 / 54.  6.100
    libavdevice    54.  0.100 / 54.  0.100
    libavfilter     2. 77.100 /  2. 77.100
    libswscale      2.  1.100 /  2.  1.100
    libswresample   0. 15.100 /  0. 15.100
    libpostproc    52.  0.100 / 52.  0.100
  [wav @ 0x13d08100] max_analyze_duration 5000000 reached at 5120000
  Guessed Channel Layout for  Input Stream #0.0 : mono
  Input #0, wav, from '10001.wav':
    Duration: 00:00:07.91, bitrate: 64 kb/s
      Stream #0:0: Audio: pcm_alaw ([6][0][0][0] / 0x0006), 8000 Hz, mono, s16, 64 kb/s
  [wav @ 0x13d08980] max_analyze_duration 5000000 reached at 5120000
  Guessed Channel Layout for  Input Stream #1.0 : mono
  Input #1, wav, from '201.wav':
    Duration: 00:00:11.88, bitrate: 128 kb/s
      Stream #1:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 8000 Hz, mono, s16, 128 kb/s
  [abuffersink @ 0x13d268c0] No opaque field provided, an AVABufferSinkParams struct is required
  

  Can anyone can help me? Thanks!

• Streaming YouTube rtsp :// on iOS

  18 mars 2014, par Jason Silberman

  I am creating an application where I want to stream rtsp:// files from YouTube. I have looked at a couple of frameworks (kxmovie), but I cannot find one that is able to stream rtsp:// and use the MPMoviePlayerController. I could create a webView, but I do not want to present the user with any of the default YouTube embed interface.

  Does anybody know if this is possible?

  Thanks!