Newest 'ffmpeg' Questions - Stack Overflow

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• Colorspace conversion in FFmpeg

  19 mars 2014, par learner

  I am looking forward to implement RGB->YUV444P colorspace conversion using FFmpeg/C++ as given on first few lines on this page. However, I am not able to excess pixel values of a frame with the FFmpeg library! Any idea how to implement this usinf FFmpeg?

• Using ffmpeg with Imagick

  19 mars 2014, par user3240613

  I am trying to generate thumbnails from videos in imagick, by extracting a single frame from them, using the ffmpeg application.

  I use this code currently:

  $image->newPseudoImage( null, null, 'ffmpeg:video.mp4[50]');
  

  It works. But it is not an ideal solution. I want to generate the thumbnail from a 50% position in the video, but i do not know how long the video is, so I can't do something like ffmpeg:video.mp4[500001]. And even if I knew the length, I still couldn't do it because running this ffmpeg:video.mp4[1000] takes almost 20 seconds to execute (ffmpeg:video.mp4[50] takes one or two seconds only).

  When i try to add some extra parameters like "ffmpeg:video.mp4[50] -ss 50" it returns error.

  The only other option I can think of, is using the exec to directly execute the ffmpeg command in the shell like "ffmpeg -i video.mp4 -vframes 1 -o screenshot.jpg" or something like that. Would that actually be more efficient solution than using the newpseudoimage method?

• php and ffmpeg, how many converts can do, once ?

  19 mars 2014, par dleline

  php and ffmpeg, how many converts can do, once

  For exemple in a simple hosting plan

  I have a php script that read remote flv files, bad things is that seeking in flash player doesn't work, so if is posible i want to pull video from seeking position with ffmpeg..

• Are the av_free* functions in ffmpeg idempotent ?

  19 mars 2014, par Dan Hook

  Specifically I'm looking at avformat_free_context. In normal execution of my code, avformat_free_context is called appropriately. I would also like to call it in the destructor of a class, in case there was an exceptional case that caused the code using the AVFormatContext to return early. Do the ffmpeg free functions behave appropriately when called on already freed data structures?

• getting errors from FFMpeg when spawned from .NET

  18 mars 2014, par Brannon

  When I run FFMpeg from the command line like this

  ffmpeg.exe -hwaccel auto -re -i "C:\Users\Public\Videos\Sample Videos\Wildlife.wmv" -an -sn -c:v bmp -pix_fmt bgr24 -f rawvideo - > junk.bin
  

  it works fine. However, when I spawn the exact same thing (minus > junk.bin) I get this nasty "bad header" error after a few seconds of playback. What is causing this? I have trouble believing my process blocks the pipe longer than the filesystem does, but it should be able to block the pipe indefinitely without defeating the decoding. The truncated stderr is below. My code to spawn the thing is here.

  ffmpeg version N-60761-g916a792 Copyright (c) 2000-2014 the FFmpeg developers
    built on Feb 19 2014 21:57:22 with gcc 4.8.2 (GCC)
    configuration: --target-os=mingw32 --enable-shared --enable-runtime-cpudetect
    libavutil      52. 65.100 / 52. 65.100
    libavcodec     55. 52.102 / 55. 52.102
    libavformat    55. 33.100 / 55. 33.100
    libavdevice    55. 10.100 / 55. 10.100
    libavfilter     4.  1.103 /  4.  1.103
    libswscale      2.  5.101 /  2.  5.101
    libswresample   0. 17.104 /  0. 17.104
  cygwin warning:
    MS-DOS style path detected: C:\Users\Public\Videos\Sample Videos\Wildlife.wmv
    Preferred POSIX equivalent is: /cygdrive/c/Users/Public/Videos/Sample Videos/Wildlife.wmv
    CYGWIN environment variable option "nodosfilewarning" turns off this warning.
    Consult the user's guide for more details about POSIX paths:
      http://cygwin.com/cygwin-ug-net/using.html#using-pathnames
  [asf @ 0x600059480] Stream #0: not enough frames to estimate rate; consider increasing probesize
  Guessed Channel Layout for  Input Stream #0.0 : stereo
  Input #0, asf, from 'C:\Users\Public\Videos\Sample Videos\Wildlife.wmv':
    Metadata:
      SfOriginalFPS   : 299700
      WMFSDKVersion   : 11.0.6001.7000
      WMFSDKNeeded    : 0.0.0.0000
      comment         : Footage: Small World Productions, Inc; Tourism New Zealand | Producer: Gary F. Spradling | Music: Steve Ball
      title           : Wildlife in HD
      copyright       : © 2008 Microsoft Corporation
      IsVBR           : 0
      DeviceConformanceTemplate: AP@L3
    Duration: 00:00:30.09, start: 0.000000, bitrate: 6977 kb/s
      Stream #0:0(eng): Audio: wmav2 (a[1][0][0] / 0x0161), 44100 Hz, stereo, fltp, 192 kb/s
      Stream #0:1(eng): Video: vc1 (Advanced) (WVC1 / 0x31435657), yuv420p, 1280x720, 5942 kb/s, 29.97 tbr, 1k tbn, 1k tbc
  Output #0, rawvideo, to 'pipe:':
    Metadata:
      SfOriginalFPS   : 299700
      WMFSDKVersion   : 11.0.6001.7000
      WMFSDKNeeded    : 0.0.0.0000
      comment         : Footage: Small World Productions, Inc; Tourism New Zealand | Producer: Gary F. Spradling | Music: Steve Ball
      title           : Wildlife in HD
      copyright       : © 2008 Microsoft Corporation
      IsVBR           : 0
      DeviceConformanceTemplate: AP@L3
      encoder         : Lavf55.33.100
      Stream #0:0(eng): Video: bmp, bgr24, 1280x720, q=2-31, 200 kb/s, 90k tbn, 29.97 tbc
  Stream mapping:
    Stream #0:1 -> #0:0 (vc1 -> bmp)
  Press [q] to stop, [?] for help
  frame=    3 fps=0.0 q=0.0 size=    8100kB time=00:00:00.10 bitrate=662902.1kbits/s    
  frame=   29 fps= 26 q=0.0 size=   78302kB time=00:00:00.96 bitrate=662902.3kbits/s    
  frame=   50 fps= 30 q=0.0 size=  135003kB time=00:00:01.66 bitrate=662902.2kbits/s    
  frame=   65 fps= 30 q=0.0 size=  175503kB time=00:00:02.16 bitrate=662902.2kbits/s    
  frame=   80 fps= 30 q=0.0 size=  216004kB time=00:00:02.66 bitrate=662902.1kbits/s    
  frame=   95 fps= 30 q=0.0 size=  256505kB time=00:00:03.16 bitrate=662902.1kbits/s    
  [asf @ 0x600059480] ff asf bad header 74  at:5053733
  [asf @ 0x600059480] invalid packet_length -1908511255 at:5053740
  [asf @ 0x600059480] ff asf bad header d4  at:5053759
  [asf @ 0x600059480] ff asf skip 55629 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5181733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5189733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5197733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5205733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5213733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5221733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5229733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5237733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5245733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5357733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5365733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5373733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5381733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5493733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5501733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5509733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5517733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5629733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5637733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5645733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5653733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5701733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5709733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5717733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5725733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5805733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5813733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5821733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5829733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5877733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5885733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5893733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5901733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5949733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5957733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5965733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] ff asf bad header 0  at:5973733
  [asf @ 0x600059480] ff asf skip 7991 (unknown stream)
  [asf @ 0x600059480] packet_obj_size invalid
      Last message repeated 15 times
  [asf @ 0x600059480] unexpected packet_replic_size of 2
  [asf @ 0x600059480] packet_obj_size invalid
      Last message repeated 7 times
  [asf @ 0x600059480] ff asf skip 2562 (unknown stream)
  [asf @ 0x600059480] packet_obj_size invalid
      Last message repeated 3 times
  [asf @ 0x600059480] ff asf skip 448 (unknown stream)
  [asf @ 0x600059480] packet_obj_size invalid
      Last message repeated 9 times
  [asf @ 0x600059480] unexpected packet_replic_size of 6
  [asf @ 0x600059480] packet_obj_size invalid
      Last message repeated 7 times
  [asf @ 0x600059480] packet_frag_size is invalid (1749-9)
  [asf @ 0x600059480] packet_obj_size invalid
      Last message repeated 13 times
  [asf @ 0x600059480] packet_frag_size is invalid (1749-9)
  [asf @ 0x600059480] packet_obj_size invalid
      Last message repeated 24 times
  [asf @ 0x600059480] unexpected packet_replic_size of 6
  [asf @ 0x600059480] packet_obj_size invalid
      Last message repeated 6 times
  [asf @ 0x600059480] unexpected packet_replic_size of 5
  [asf @ 0x600059480] packet_obj_size invalid
      Last message repeated 6 times
  [asf @ 0x600059480] packet_frag_size is invalid (1749-9)
  [asf @ 0x600059480] packet_obj_size invalid
  [asf @ 0x600059480] packet_frag_size is invalid (1749-9)
  [asf @ 0x600059480] packet_obj_size invalid
      Last message repeated 2 times
  [asf @ 0x600059480] unexpected packet_replic_size of 5
  [asf @ 0x600059480] packet_obj_size invalid
      Last message repeated 8 times
  [asf @ 0x600059480] unexpected packet_replic_size of 5
  [asf @ 0x600059480] packet_obj_size invalid
      Last message repeated 39 times
  [asf @ 0x600059480] packet_frag_size is invalid (1749-40)