Newest 'ffmpeg' Questions - Stack Overflow

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• "No accelerated colorspace conversion found from yuv420p to bgr24" when using OpenCV with FFMPEG on mac

  31 octobre 2011, par Itay k

  When trying to acquire a frame from a video file (I've tried several video formats) I am getting an error message "No accelerated colorspace conversion found from yuv420p to bgr24". The exact same code ran perfectly fine on a windows machine and I couldn't get it to run on a mac even after I recompiled and installed FFMPEG and OpenCV. I am using lion for my OS. Any ideas?

• How can you only extract 30 seconds of audio using ffmpeg

  30 octobre 2011, par Jaggu

  I am using ffmpeg for audio conversion. I am using this command:

  ffmpeg -i file.mp3 file.wav
  

  This works fine. However I only want to my output file to contain maximum 1 minute of audio. How can I do that using ffmpeg?

• ffmpeg mozilla mp3 to webm encoding issue

  30 octobre 2011, par Jaggu

  I want to encode my mp3 file into webm format so that it can be played in Firefox using HTML5 natively.

  This is the file that is converted format using ffmpeg using command:

  http://www.filesonic.in/file/2825764155

  ffmpeg -i test.mp3 -ab 128k test.webm
  

  The file gets converted successfully and I can play in firefox and chrome using HTML5's native audio feature.

  However problem is in FF when I want to jump to a particular second using slider it doesn't work anymore. It just stops playing. This problem doesn't occur in chrome etc.

  What can be the issue?

  Update: I tested in FF 7.0.1 and it still doesn't work.

• Windows media player showing wrong bit rate

  30 octobre 2011, par Akash

  I used ffmpeg to change the bit rate of a .mp3 file from 128kbps to 64kbps

  here are the final lines of output of ffmpeg:

  size=    2261kB time=00:04:49.38 bitrate=  64.0kbits/s
  video:0kB audio:2261kB global headers:0kB muxing overhead 0.011274%
  

  Tough the file size is reduced by half, windows media player while playing the file shows the bit-rate is 159 K bits/second

  Any ideas on why is this so?

• Getting incorrect output resolution ffmpeg

  29 octobre 2011, par Adam

  I am capturing an RTSP stream from a security camera, and transcoding it for (live streaming) to iphone, using OSX as the encoding platform. I have it working correctly, and Im tuning it. However, it seems that it is not outputting the requested resolution. This is my script

  /Applications/SecurityCamera/openRTSP -v -c -t rtsp://10.0.1.118/ch1-s1 | \
      /Applications/SecurityCamera/ffmpeg \
      -r 10 -i - \
      -y -an -ab 64000 -f mpegts -vcodec copy -s 960x640 \
      -flags +loop -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 \
      -subq 5 -trellis 1 -refs 1 -coder 0 -me_range 16  -keyint_min 25 -sc_threshold 40 \
      -i_qfactor 0.71 -bt 400k -maxrate 524288 -bufsize 524288 \
      -qcomp 0.6 -qmin 10 -qmax 51 -qdiff 4 -level 30 \
      -aspect 960:640 -r 10 -g 10 -async 2 -\
      | /Applications/SecurityCamera/mediastreamsegmenter -b http://hydracam.dyndns.org:8080/ -f /Library/WebServer/Documents/ -i stream.m3u8 -t 10 -s 4 -D
  

  This is the status report:

  Input #0, h264, from 'pipe:':
  
    Duration: N/A, bitrate: N/A
    Stream #0.0: Video: h264, yuv420p, 1600x1200, 10 fps, 10 tbr, 1200k tbn, 20 tbc
    [mpegts @ 0x10100c200] muxrate VBR, pcr every 1 pkts, sdt every 200, pat/pmt every 40 pkts
    Output #0, mpegts, to 'pipe:':
    Metadata:
      encoder         : Lavf52.93.0
      Stream #0.0: Video: libx264, yuv420p, 1600x1200 [PAR 1:1 DAR 4:3], q=2-31, 90k tbn, 10 tbc
  Stream mapping:
    Stream #0.0 -> #0.0
  

  You can see that its working, but it is outputting 1600x1200 for some reason.

  If I change the -vcodec copy to -vcodec libx264 then I get the correct status report (stating 960x640, correct), but the streaming halts after 54 frames (see output below)

  Seems stream 0 codec frame rate differs from container frame rate: 20.00 (20/1) -> 10.00 (20/2)
  Input #0, h264, from 'pipe:':
    Duration: N/A, bitrate: N/A
      Stream #0.0: Video: h264, yuv420p, 1600x1200, 10 fps, 10 tbr, 1200k tbn, 20 tbc
  [buffer @ 0x100d02420] w:1600 h:1200 pixfmt:yuv420p
  [scale @ 0x100d026f0] w:1600 h:1200 fmt:yuv420p -> w:960 h:640 fmt:yuv420p flags:0x4
  [libx264 @ 0x10100d400] using SAR=1/1
  [libx264 @ 0x10100d400] frame MB size (60x40) > level limit (1620)
  [libx264 @ 0x10100d400] using cpu capabilities: MMX2 SSE2Fast SSSE3 Cache64 SlowCTZ SlowAtom
  [libx264 @ 0x10100d400] profile Constrained Baseline, level 3.0
  [mpegts @ 0x10100c200] muxrate VBR, pcr every 1 pkts, sdt every 200, pat/pmt every 40 pkts
  Output #0, mpegts, to 'pipe:':
    Metadata:
      encoder         : Lavf52.93.0
      Stream #0.0: Video: libx264, yuv420p, 960x640 [PAR 1:1 DAR 3:2], q=10-51, 200 kb/s, 90k tbn, 10 tbc
  Stream mapping:
    Stream #0.0 -> #0.0
  read pmap fffps=  3 q=37.0 size=      37kB time=0.10 bitrate=3008.0kbits/s    bits/s    
  video pid set at 100
  found sequence start
    next segment value 1026000
  written bytes 376 skipped 0
  frame=   54 fps=  2 q=-1.0 Lsize=     160kB time=5.40 bitrate= 242.0kbits/s    
  video:141kB audio:0kB global headers:0kB muxing overhead 12.872737%
  frame I:6     Avg QP:34.68  size: 23524
  [libx264 @ 0x10100d400] frame P:48    Avg QP:41.53  size:    75
  [libx264 @ 0x10100d400] mb I  I16..4: 63.9%  0.0% 36.1%
  [libx264 @ 0x10100d400] mb P  I16..4:  0.1%  0.0%  0.0%  P16..4:  0.8%  0.1%  0.0%  0.0%  0.0%    skip:99.0%
  [libx264 @ 0x10100d400] final ratefactor: 38.54
  [libx264 @ 0x10100d400] coded y,uvDC,uvAC intra: 57.7% 22.3% 2.0% inter: 0.0% 0.1% 0.0%
  [libx264 @ 0x10100d400] i16 v,h,dc,p: 23% 35% 27% 15%
  [libx264 @ 0x10100d400] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 23% 32% 16%  4%  3%  3%  7%  4%  8%
  [libx264 @ 0x10100d400] i8c dc,h,v,p: 83% 11%  5%  0%
  [libx264 @ 0x10100d400] kb/s:214.43