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• ffmpeg : AVI to FLV conversion doubles file size

  22 septembre 2012, par weekens

  I convert AVI to FLV with ffmpeg using -sameq parameter (same quality):

  ffmpeg -i test.avi -sameq -f flv sameq.flv
  

  The resulting file has the same video and audio quality as the original, but it's more than twice the original file size:

  84M sameq.flv
  41M test.avi
  

  Why does it happen?

  Transcoder output:

  ffmpeg version N-34750-g070d2d7, Copyright (c) 2000-2011 the FFmpeg developers
    built on Nov 12 2011 11:23:07 with gcc 4.6.1
    configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-postproc --enable-libfaac --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --enable-x11grab
    libavutil    51. 24. 1 / 51. 24. 1
    libavcodec   53. 33. 0 / 53. 33. 0
    libavformat  53. 20. 0 / 53. 20. 0
    libavdevice  53.  4. 0 / 53.  4. 0
    libavfilter   2. 48. 0 /  2. 48. 0
    libswscale    2.  1. 0 /  2.  1. 0
    libpostproc  51.  2. 0 / 51.  2. 0
  Input #0, avi, from 'test.avi':
    Duration: 00:06:30.00, start: 0.000000, bitrate: 866 kb/s
      Stream #0:0: Video: mpeg4 (Advanced Real Time Simple Profile) (DIVX / 0x58564944), yuv420p, 400x300 [SAR 1:1 DAR 4:3], 25 tbr, 25 tbn, 25 tbc
      Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 44100 Hz, mono, s16, 64 kb/s
  [buffer @ 0xa247ae0] w:400 h:300 pixfmt:yuv420p tb:1/1000000 sar:1/1 sws_param:
  Output #0, flv, to 'sameq.flv':
    Metadata:
      encoder         : Lavf53.20.0
      Stream #0:0: Video: flv1 ([2][0][0][0] / 0x0002), yuv420p, 400x300 [SAR 1:1 DAR 4:3], q=2-31, 200 kb/s, 1k tbn, 25 tbc
      Stream #0:1: Audio: mp3 ([2][0][0][0] / 0x0002), 44100 Hz, mono, s16, 128 kb/s
  Stream mapping:
    Stream #0:0 -> #0:0 (mpeg4 -> flv)
    Stream #0:1 -> #0:1 (mp3 -> libmp3lame)
  Press [q] to stop, [?] for help
  frame= 9742 fps=255 q=0.0 Lsize=   85074kB time=00:06:30.00 bitrate=1787.0kbits/s    
  video:79163kB audio:5525kB global headers:0kB muxing overhead 0.455568%
  

• how to use ffmpeg/libavcodec/libstagefright

  22 septembre 2012, par 7bigtrees

  I just have a question about how to use ffmpeg/libavcodec/libstagfright.cpp: I try to avcodec_open2(st->codec, codec) when I have use ffmpeg to set codec->id as CODEC_ID_H264,codec->name as libstagefright_h264,that means I will open AVCodec ff_libstagefright_h264_decoder.

  but when Stagefright_init->OMXCodec::Create->configureCodec-> initOutputFormat(meta), the process just Quit ! It is a bazinga !

  I knew that meta is Metadata, its data comes from codec->extradata, and in here, it means sps and pps, am I right?

  How can I use libstagefright sucessfully in ffmpeg? Can somebody give me an example?

• "Transcode" copying video/audio codec

  22 septembre 2012, par JunCTionS

  I took some very shaky video, and went online to try and find how to stabilize it. I came upon this nice blog that uses transcode for it. Following the blog instructions it worked very nice, but the end result had a lot of compression artifacts. This I imagine is mostly due to using xvid as a new codec.

  My intention is reuse the codec the camera originally used which is H.264/AVC but I haven't found a way of doing so (ran into various dead ends using either encoder -y mov... or -y ffpmeg.

  In particular when using -y ffmpeg -F "-vcodec copy -acodec copy" it prints out:

  [export_ffmpeg.so] warning: Video template standard must be one of pal/ntsc
  

  but running

  ffmpeg -i input.mov -vcodec copy -acodec copy output.mov
  

  Presents no problem.

  Any idea on how to do this? or an alternative to stabilize video on linux?.

• ffmpeg convert to mp4 and ogg. Where error ?

  21 septembre 2012, par John Smith

  Next code create convert video files but they are bad - files not play. Tell me please where error?

  shell_exec("ffmpeg -i $infile_ogg -v 10 $outfile_mp4 2>&1");
  shell_exec("ffmpeg -i $infile_mp4 -v 10 $outfile_ogg 2>&1");
  

  i use code:

  $outfile_mp4=$_SERVER['DOCUMENT_ROOT'].'/10001/ConcertMedia/1348213376.mp4';
  $outfile_ogg=$_SERVER['DOCUMENT_ROOT'].'/10001/ConcertMedia/1348213376.ogg';
  echo $outfile_mp4.'
  '.'
  '.$outfile_ogg.'
  '.shell_exec("ffmpeg -i $outfile_mp4 -V 10 $ outfile_ogg 2> & 1");
  

  but i see only:

  /hsphere/local/home/c292729/testwork.ru/10001/ConcertMedia/1348213376.mp4
  
  /hsphere/local/home/c292729/testwork.ru/10001/ConcertMedia/1348213376.ogg
  

  i not see consol log....

  I will take any help

• How to record video using ffmpeg on android ?

  21 septembre 2012, par Junaid

  I want to create a video using ffmpeg by taking byte[] data from Android Camera. Now the problem is i don't have much knowledge about ffmpeg. So i need some documentation on ffmpeg. I will appreciate if anyone can provide some useful tutorial / sample code / example on ffmpeg and how it works , how it can be used to create video programmatically, Thanks.