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• ALSA buffer xrun induced by low quality source in ffmpeg capture

  8 janvier 2021, par Peter Becich

  I am attempting to transfer some old Video 8 tapes to my computer, though an EasyCap USB stick and the motherboard's sound line-in, on Ubuntu. I believe the arguments are correctly laid out below to capture from two independent streams, and encode them both into the output MP4 file.

  



  Edit :

  



  I can simplify the question a bit, now.

  



  ALSA buffer overrun (or underrun ?) is induced by the unreliable/noisy audio source. For instance, if ffmpeg captures the beginning of tape playback, this causes "buffer xrun" far beyond when the tape gets up to speed and playback should be normal.

  



  It is interesting that the bitrate shown in the ffmpeg log shoots up higher than normal when it's producing a garbage output ! (Is this bitrate a sum of of audio and video bitrates ?)

  



  I've tried a couple of audio encoding codecs, and had the same problem.

  



  Using libfdk_aac :

  



    Metadata:
    encoder         : Lavf56.15.102
    Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv422p, 640x480, q=-1--1, 29.97 fps, 11988 tbn, 29.97 tbc
    Metadata:
      encoder         : Lavc56.13.100 libx264
    Stream #0:1: Audio: aac (libfdk_aac) ([64][0][0][0] / 0x0040), 48000 Hz, mono, s16, 128 kb/s
    Metadata:
      encoder         : Lavc56.13.100 libfdk_aac
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
  Stream #1:0 -> #0:1 (pcm_s16le (native) -> aac (libfdk_aac))
[alsa @ 0x22038a0] ALSA buffer xrun.  0kB time=00:00:00.00 bitrate=N/A    
[alsa @ 0x22038a0] ALSA buffer xrun.1934kB time=00:00:02.76 bitrate=5723.5kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.4795kB time=00:00:05.49 bitrate=7150.1kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.7668kB time=00:00:08.21 bitrate=7646.1kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.1475kB time=00:00:10.94 bitrate=8588.9kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.3822kB time=00:00:13.66 bitrate=8289.0kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.5388kB time=00:00:16.38 bitrate=7695.0kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.6896kB time=00:00:19.10 bitrate=7244.0kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.8980kB time=00:00:21.84 bitrate=7118.8kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.2032kB time=00:00:24.55 bitrate=7349.3kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.4612kB time=00:00:27.27 bitrate=7391.1kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.6660kB time=00:00:29.98 bitrate=7284.6kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.9123kB time=00:00:32.68 bitrate=7299.3kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.0641kB time=00:00:35.39 bitrate=7091.7kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.2601kB time=00:00:38.13 bitrate=7002.6kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.5828kB time=00:00:40.87 bitrate=7181.0kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.8481kB time=00:00:43.60 bitrate=7229.9kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.1461kB time=00:00:46.34 bitrate=7328.0kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.3982kB time=00:00:49.06 bitrate=7342.7kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.6565kB time=00:00:51.77 bitrate=7367.8kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.9718kB time=00:00:54.51 bitrate=7471.3kbits/s    
[alsa @ 0x22038a0] ALSA buffer xrun.2341kB time=00:00:57.25 bitrate=7489.2kbits/s    
^Cframe= 1760 fps= 29 q=-1.0 Lsize=   53946kB time=00:01:00.04 bitrate=7360.3kbits/s    
video:53880kB audio:53kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.022994%
[libx264 @ 0x2217ac0] frame I:8     Avg QP:24.00  size: 55686
[libx264 @ 0x2217ac0] frame P:1752  Avg QP:27.66  size: 31237
[libx264 @ 0x2217ac0] mb I  I16..4: 100.0%  0.0%  0.0%
[libx264 @ 0x2217ac0] mb P  I16..4: 15.0%  0.0%  0.0%  P16..4: 80.2%  0.0%  0.0%  0.0%  0.0%    skip: 4.8%
[libx264 @ 0x2217ac0] coded y,uvDC,uvAC intra: 45.3% 86.6% 59.4% inter: 65.7% 81.3% 11.5%
[libx264 @ 0x2217ac0] i16 v,h,dc,p: 40% 25% 26%  9%
[libx264 @ 0x2217ac0] i8c dc,h,v,p: 45% 24% 19% 12%
[libx264 @ 0x2217ac0] kb/s:7516.07
Received signal 2: terminating.


  



  Using libvorbis :

  



    Metadata:
    encoder         : Lavf56.15.102
    Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv422p, 640x480, q=-1--1, 29.97 fps, 11988 tbn, 29.97 tbc
    Metadata:
      encoder         : Lavc56.13.100 libx264
    Stream #0:1: Audio: vorbis (libvorbis) ([221][0][0][0] / 0x00DD), 48000 Hz, mono, fltp, 128 kb/s
    Metadata:
      encoder         : Lavc56.13.100 libvorbis
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
  Stream #1:0 -> #0:1 (pcm_s16le (native) -> vorbis (libvorbis))
[alsa @ 0x1a948a0] ALSA buffer xrun.  0kB time=00:00:00.00 bitrate=N/A    
[alsa @ 0x1a948a0] ALSA buffer xrun. 402kB time=00:00:04.37 bitrate= 752.3kbits/s    
[alsa @ 0x1a948a0] ALSA buffer xrun.4122kB time=00:00:08.80 bitrate=3833.0kbits/s    
[alsa @ 0x1a948a0] ALSA buffer xrun.8722kB time=00:00:13.14 bitrate=5436.3kbits/s    
[alsa @ 0x1a948a0] ALSA buffer xrun.3903kB time=00:00:17.51 bitrate=6502.2kbits/s    
[alsa @ 0x1a948a0] ALSA buffer xrun.6625kB time=00:00:21.89 bitrate=6221.4kbits/s    
[alsa @ 0x1a948a0] ALSA buffer xrun.9548kB time=00:00:26.28 bitrate=6092.5kbits/s    
^Cframe=  851 fps= 26 q=-1.0 Lsize=   22018kB time=00:00:30.69 bitrate=5875.3kbits/s    
video:21996kB audio:12kB subtitle:0kB other streams:0kB global headers:4kB muxing overhead: 0.044897%
[libx264 @ 0x1aa8ac0] frame I:4     Avg QP:23.50  size: 62405
[libx264 @ 0x1aa8ac0] frame P:847   Avg QP:25.58  size: 26297
[libx264 @ 0x1aa8ac0] mb I  I16..4: 100.0%  0.0%  0.0%
[libx264 @ 0x1aa8ac0] mb P  I16..4: 13.2%  0.0%  0.0%  P16..4: 72.0%  0.0%  0.0%  0.0%  0.0%    skip:14.8%
[libx264 @ 0x1aa8ac0] coded y,uvDC,uvAC intra: 40.6% 81.0% 58.6% inter: 58.8% 72.7% 8.6%
[libx264 @ 0x1aa8ac0] i16 v,h,dc,p: 41% 28% 22%  9%
[libx264 @ 0x1aa8ac0] i8c dc,h,v,p: 54% 19% 16% 11%
[libx264 @ 0x1aa8ac0] kb/s:6345.60
Received signal 2: terminating.


  



  ---

  



  ffmpeg's detection of the ALSA stream is seemingly goofed up by the inconsistencies of the tape. In the failure case, only short blips of the tapes audio exist in the output MP4. The audio bitrate of the output file is less than 10 kbps, averaged out across the whole file. The output video seems to be fine, even though the low frames-per-second in the failure case log below.

  



  The audio and video streams can be captured fine for short amounts of time before a source error occurs ; this provides the success case log. The failure case log was created by intentionally making an error in the source streams — turning on the camera makes a brief noisy signal.

  



  Is there a setting that needs to be forced to keep ffmpeg recording the audio stream, even when the tape is blank or noisy ?

  



  Could it be that the libfdk_aac audio encoder is tripped up by the low quality source ?

  



  The relevant line ; rawvideo stream is piped to this in script at bottom :

  



  ffmpeg -pixel_format uyvy422 -s:v 720x480 -framerate 29.97 -f rawvideo \
-i $PIPE  -f alsa -i hw:0,0 -vf scale=w=720:h=540 -vcodec libx264 \
-preset ultrafast -shortest -c:a libfdk_aac -b:a 128k -af pan=1:c0=c0  \
-ar 96000 $OUTFILE


  



  The ar argument was one attempt to force recording.

  



  ffmpeg log file for (short-lived) success ; high frames-per-second captured :

  



  ffmpeg version 2.5.3 Copyright (c) 2000-2015 the FFmpeg developers
  built on Jan 11 2015 17:53:45 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
  configuration: --extra-libs=-ldl --prefix=/opt/ffmpeg --enable-avresample --disable-debug --enable-nonfree --enable-gpl --enable-version3 --enable-libpulse --enable-libopencore-amrnb --enable-libopencore-amrwb --disable-decoder=amrnb --disable-decoder=amrwb --enable-libx264 --enable-libx265 --enable-libfdk-aac --enable-libvorbis --enable-libmp3lame --enable-libopus --enable-libvpx --enable-libspeex --enable-libass --enable-avisynth --enable-libsoxr --enable-libxvid --enable-libvo-aacenc --enable-libvidstab
  libavutil      54. 15.100 / 54. 15.100
  libavcodec     56. 13.100 / 56. 13.100
  libavformat    56. 15.102 / 56. 15.102
  libavdevice    56.  3.100 / 56.  3.100
  libavfilter     5.  2.103 /  5.  2.103
  libavresample   2.  1.  0 /  2.  1.  0
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  3.100 / 53.  3.100
Input #0, rawvideo, from '/tmp/somagic-pipe':
  Duration: N/A, start: 0.000000, bitrate: 165722 kb/s
    Stream #0:0: Video: rawvideo (UYVY / 0x59565955), uyvy422, 720x480, 165722 kb/s, 29.97 tbr, 29.97 tbn, 29.97 tbc
Home directory not accessible: Permission denied
Guessed Channel Layout for  Input Stream #1.0 : stereo
Input #1, alsa, from 'hw:0,0':
  Duration: N/A, start: 1423202268.577088, bitrate: 1536 kb/s
    Stream #1:0: Audio: pcm_s16le, 48000 Hz, 2 channels, s16, 1536 kb/s
No pixel format specified, yuv422p for H.264 encoding chosen.
Use -pix_fmt yuv420p for compatibility with outdated media players.
[Parsed_pan_0 @ 0x3335d60] This syntax is deprecated. Use '|' to separate the list items.
Single channel layout '1' is interpreted as a number of channels, switch to the syntax '1c' otherwise it will be interpreted as a channel layout number in a later version
[Parsed_pan_0 @ 0x3335d60] Pure channel mapping detected: 0
[libx264 @ 0x3364bc0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.1 Cache64
[libx264 @ 0x3364bc0] profile High 4:2:2, level 3.1, 4:2:2 8-bit
[libx264 @ 0x3364bc0] 264 - core 142 r2389 956c8d8 - H.264/MPEG-4 AVC codec - Copyleft 2003-2014 - http://www.videolan.org/x264.html - options: cabac=0 ref=1 deblock=0:0:0 analyse=0:0 me=dia subme=0 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=3 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=0 keyint=250 keyint_min=25 scenecut=0 intra_refresh=0 rc=crf mbtree=0 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=0
Output #0, mp4, to '/home/peterbecich/easycap/Videos/fpv_video_02_05_2015_21_57_48.mp4':
  Metadata:
    encoder         : Lavf56.15.102
    Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv422p, 720x540, q=-1--1, 29.97 fps, 11988 tbn, 29.97 tbc
    Metadata:
      encoder         : Lavc56.13.100 libx264
    Stream #0:1: Audio: aac (libfdk_aac) ([64][0][0][0] / 0x0040), 96000 Hz, mono, s16, 128 kb/s
    Metadata:
      encoder         : Lavc56.13.100 libfdk_aac
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
  Stream #1:0 -> #0:1 (pcm_s16le (native) -> aac (libfdk_aac))
Press [q] to stop, [?] for help
frame=   13 fps=0.0 q=26.0 size=     187kB time=00:00:00.30 bitrate=5102.7kbits/s    
frame=   29 fps= 29 q=26.0 size=     469kB time=00:00:00.83 bitrate=4607.6kbits/s    
frame=   44 fps= 29 q=26.0 size=     755kB time=00:00:01.33 bitrate=4635.2kbits/s    
frame=   59 fps= 29 q=26.0 size=    1024kB time=00:00:01.83 bitrate=4572.1kbits/s    
frame=   74 fps= 29 q=26.0 size=    1279kB time=00:00:02.33 bitrate=4486.5kbits/s    
frame=   89 fps= 29 q=26.0 size=    1516kB time=00:00:02.83 bitrate=4378.0kbits/s    
frame=  104 fps= 29 q=26.0 size=    1752kB time=00:00:03.33 bitrate=4301.0kbits/s    
frame=  119 fps= 29 q=26.0 size=    1991kB time=00:00:03.83 bitrate=4251.1kbits/s    
frame=  135 fps= 30 q=26.0 size=    2245kB time=00:00:04.37 bitrate=4207.5kbits/s    
frame=  150 fps= 30 q=26.0 size=    2524kB time=00:00:04.87 bitrate=4245.0kbits/s    
frame=  165 fps= 30 q=26.0 size=    2808kB time=00:00:05.37 bitrate=4282.0kbits/s    
frame=  180 fps= 30 q=26.0 size=    3091kB time=00:00:05.87 bitrate=4311.5kbits/s    
[rawvideo @ 0x3350640] Invalid buffer size, packet size 65536 < expected frame_size 691200
Error while decoding stream #0:0: Invalid argument
frame=  183 fps= 29 q=-1.0 Lsize=    3247kB time=00:00:06.11 bitrate=4351.5kbits/s    
video:3142kB audio:96kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.254788%
[libx264 @ 0x3364bc0] frame I:1     Avg QP:20.00  size:  2289
[libx264 @ 0x3364bc0] frame P:182   Avg QP:25.99  size: 17664
[libx264 @ 0x3364bc0] mb I  I16..4: 100.0%  0.0%  0.0%
[libx264 @ 0x3364bc0] mb P  I16..4: 78.5%  0.0%  0.0%  P16..4: 20.2%  0.0%  0.0%  0.0%  0.0%    skip: 1.4%
[libx264 @ 0x3364bc0] coded y,uvDC,uvAC intra: 84.1% 71.5% 18.9% inter: 51.9% 63.5% 0.4%
[libx264 @ 0x3364bc0] i16 v,h,dc,p: 15%  8% 69%  8%
[libx264 @ 0x3364bc0] i8c dc,h,v,p: 50% 19% 24%  7%
[libx264 @ 0x3364bc0] kb/s:4215.02


  



  ffmpeg log for failure ; low FPS captured :

  



  ffmpeg version 2.5.3 Copyright (c) 2000-2015 the FFmpeg developers
  built on Jan 11 2015 17:53:45 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
  configuration: --extra-libs=-ldl --prefix=/opt/ffmpeg --enable-avresample --disable-debug --enable-nonfree --enable-gpl --enable-version3 --enable-libpulse --enable-libopencore-amrnb --enable-libopencore-amrwb --disable-decoder=amrnb --disable-decoder=amrwb --enable-libx264 --enable-libx265 --enable-libfdk-aac --enable-libvorbis --enable-libmp3lame --enable-libopus --enable-libvpx --enable-libspeex --enable-libass --enable-avisynth --enable-libsoxr --enable-libxvid --enable-libvo-aacenc --enable-libvidstab
  libavutil      54. 15.100 / 54. 15.100
  libavcodec     56. 13.100 / 56. 13.100
  libavformat    56. 15.102 / 56. 15.102
  libavdevice    56.  3.100 / 56.  3.100
  libavfilter     5.  2.103 /  5.  2.103
  libavresample   2.  1.  0 /  2.  1.  0
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  3.100 / 53.  3.100
Input #0, rawvideo, from '/tmp/somagic-pipe':
  Duration: N/A, start: 0.000000, bitrate: 165722 kb/s
    Stream #0:0: Video: rawvideo (UYVY / 0x59565955), uyvy422, 720x480, 165722 kb/s, 29.97 tbr, 29.97 tbn, 29.97 tbc
Home directory not accessible: Permission denied
Guessed Channel Layout for  Input Stream #1.0 : stereo
Input #1, alsa, from 'hw:0,0':
  Duration: N/A, start: 1423201999.226455, bitrate: 1536 kb/s
    Stream #1:0: Audio: pcm_s16le, 48000 Hz, 2 channels, s16, 1536 kb/s
No pixel format specified, yuv422p for H.264 encoding chosen.
Use -pix_fmt yuv420p for compatibility with outdated media players.
[Parsed_pan_0 @ 0x21cad60] This syntax is deprecated. Use '|' to separate the list items.
Single channel layout '1' is interpreted as a number of channels, switch to the syntax '1c' otherwise it will be interpreted as a channel layout number in a later version
[Parsed_pan_0 @ 0x21cad60] Pure channel mapping detected: 0
[libx264 @ 0x21f9bc0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.1 Cache64
[libx264 @ 0x21f9bc0] profile High 4:2:2, level 3.1, 4:2:2 8-bit
[libx264 @ 0x21f9bc0] 264 - core 142 r2389 956c8d8 - H.264/MPEG-4 AVC codec - Copyleft 2003-2014 - http://www.videolan.org/x264.html - options: cabac=0 ref=1 deblock=0:0:0 analyse=0:0 me=dia subme=0 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=3 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=0 keyint=250 keyint_min=25 scenecut=0 intra_refresh=0 rc=crf mbtree=0 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=0
Output #0, mp4, to '/home/peterbecich/easycap/Videos/fpv_video_02_05_2015_21_53_18.mp4':
  Metadata:
    encoder         : Lavf56.15.102
    Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv422p, 720x540, q=-1--1, 29.97 fps, 11988 tbn, 29.97 tbc
    Metadata:
      encoder         : Lavc56.13.100 libx264
    Stream #0:1: Audio: aac (libfdk_aac) ([64][0][0][0] / 0x0040), 96000 Hz, mono, s16, 128 kb/s
    Metadata:
      encoder         : Lavc56.13.100 libfdk_aac
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
  Stream #1:0 -> #0:1 (pcm_s16le (native) -> aac (libfdk_aac))
Press [q] to stop, [?] for help
frame=    1 fps=0.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
frame=    1 fps=1.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
frame=    1 fps=0.7 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
frame=    1 fps=0.5 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
frame=    1 fps=0.4 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
frame=    1 fps=0.3 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
frame=    1 fps=0.3 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
frame=    1 fps=0.2 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
frame=    1 fps=0.2 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
frame=    1 fps=0.2 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
frame=    1 fps=0.2 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A    
[alsa @ 0x21e5ac0] ALSA buffer xrun.
frame=    8 fps=1.3 q=19.0 size=      12kB time=00:00:06.03 bitrate=  15.9kbits/s    
frame=   23 fps=3.5 q=18.0 size=      12kB time=00:00:06.03 bitrate=  16.4kbits/s    
frame=   38 fps=5.4 q=18.0 size=      12kB time=00:00:06.03 bitrate=  16.7kbits/s    
frame=   53 fps=7.0 q=18.0 size=      12kB time=00:00:06.03 bitrate=  16.9kbits/s    
frame=   68 fps=8.4 q=26.0 size=     146kB time=00:00:06.03 bitrate= 198.8kbits/s    
frame=   83 fps=9.7 q=26.0 size=     375kB time=00:00:06.03 bitrate= 510.0kbits/s    
frame=   98 fps= 11 q=26.0 size=     608kB time=00:00:06.03 bitrate= 826.5kbits/s    
frame=  114 fps= 12 q=26.0 size=     875kB time=00:00:06.03 bitrate=1189.1kbits/s    
frame=  128 fps= 13 q=26.0 size=    1091kB time=00:00:06.03 bitrate=1481.6kbits/s    
frame=  144 fps= 14 q=26.0 size=    1339kB time=00:00:06.03 bitrate=1819.2kbits/s    
frame=  159 fps= 14 q=26.0 size=    1571kB time=00:00:06.03 bitrate=2134.6kbits/s    
frame=  174 fps= 15 q=26.0 size=    1796kB time=00:00:06.03 bitrate=2440.1kbits/s    
[alsa @ 0x21e5ac0] ALSA buffer xrun.
frame=  189 fps= 16 q=26.0 size=    2015kB time=00:00:12.04 bitrate=1370.4kbits/s    
frame=  204 fps= 16 q=26.0 size=    2238kB time=00:00:12.04 bitrate=1522.3kbits/s    
frame=  219 fps= 17 q=26.0 size=    2490kB time=00:00:12.04 bitrate=1694.2kbits/s    
frame=  235 fps= 17 q=26.0 size=    2728kB time=00:00:12.04 bitrate=1855.8kbits/s    
frame=  250 fps= 18 q=26.0 size=    2973kB time=00:00:12.04 bitrate=2022.4kbits/s    
[rawvideo @ 0x21e5640] Invalid buffer size, packet size 65536 < expected frame_size 691200
Error while decoding stream #0:0: Invalid argument
frame=  261 fps= 18 q=-1.0 Lsize=    3269kB time=00:00:12.06 bitrate=2220.1kbits/s    
video:3263kB audio:4kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.081101%
[libx264 @ 0x21f9bc0] frame I:2     Avg QP:21.50  size: 21342
[libx264 @ 0x21f9bc0] frame P:259   Avg QP:24.22  size: 12734
[libx264 @ 0x21f9bc0] mb I  I16..4: 100.0%  0.0%  0.0%
[libx264 @ 0x21f9bc0] mb P  I16..4: 62.8%  0.0%  0.0%  P16..4: 14.2%  0.0%  0.0%  0.0%  0.0%    skip:22.9%
[libx264 @ 0x21f9bc0] coded y,uvDC,uvAC intra: 77.7% 61.2% 14.1% inter: 19.7% 24.8% 1.6%
[libx264 @ 0x21f9bc0] i16 v,h,dc,p: 17% 10% 65%  8%
[libx264 @ 0x21f9bc0] i8c dc,h,v,p: 52% 18% 24%  6%
[libx264 @ 0x21f9bc0] kb/s:3068.90


  



  The whole script :

  



  #!/bin/sh

PIPE=/tmp/somagic-pipe
OUTFILEDIR=~/easycap/Videos/
LOGDIR=~/.somagic-log/
NOW=`date +"%m_%d_%Y_%H_%M_%S"`

OUTFILE=${OUTFILEDIR}fpv_video_${NOW}.mp4

mkdir $LOGDIR

FFMPEG_LOG=${LOGDIR}ffmpeg.log
SOMAGIC_LOG=${LOGDIR}somagic.log
MPLAYER_LOG=${LOGDIR}mplayer.log

rm $PIPE >/dev/null 2>&1
rm $OUTFILE >/dev/null 2>&1

rm $FFMPEG_LOG
rm $SOMAGIC_LOG
rm $MPLAYER_LOG

mkfifo $PIPE >/dev/null 2>&1

ffmpeg -pixel_format uyvy422 -s:v 720x480 -framerate 29.97 -f rawvideo \
-i $PIPE  -f alsa -i hw:0,0 -vf scale=w=720:h=540 -vcodec libx264 \
-preset ultrafast -shortest -c:a libfdk_aac -b:a 128k -af pan=1:c0=c0  \
-ar 96000 $OUTFILE > $FFMPEG_LOG 2>&1 &

somagic-capture --ntsc -c --luminance=2 --lum-aperture=3 2> $SOMAGIC_LOG \
| tee $PIPE | \
mplayer -vf yadif,screenshot -demuxer rawvideo -rawvideo \
"ntsc:format=uyvy:fps=30000/1001" -aspect 4:3 - 2> $MPLAYER_LOG


rm $PIPE >/dev/null 2>&1 


  



  Modified from here : https://gist.github.com/Brick85/0b327ac2d3d45e23ed33

  


• Using FFmpeg with URL input causes SIGSEGV in AWS Lambda (Python runtime)

  26 mars, par Dave94

  I'm trying to implement a video converting solution on AWS Lambda following their article named Processing user-generated content using AWS Lambda and FFmpeg.
However when I run my command with subprocess.Popen() it returns -11 which translates to SIGSEGV (segmentation fault).
I've tried to process the video with the newest (4.3.1) static build from John Van Sickle's site as with the "official" ffmpeg-lambda-layer but it seems like it doesn't matter which one I use, the result is the same.

  


  If I download the video to the Lambda's /tmp directory and add this downloaded file as an input to FFmpeg it works correctly (with the same parameters). However I'm trying to prevent this as the /tmp directory's max. size is only 512 MB which is not quite enough for me.

  


  The relevant code which returns SIGSEGV :

  


  ffmpeg_cmd = '/opt/bin/ffmpeg -stream_loop -1 -i "' + s3_source_signed_url + '" -i /opt/bin/audio.mp3 -i /opt/bin/watermark.png -shortest -y -deinterlace -vcodec libx264 -pix_fmt yuv420p -preset veryfast -r 30 -g 60 -b:v 4500k -c:a copy -map 0:v:0 -map 1:a:0 -filter_complex scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2,setsar=1,overlay=(W-w)/2:(H-h)/2,format=yuv420p -loglevel verbose -f flv -'
command1 = shlex.split(ffmpeg_cmd)
p1 = subprocess.Popen(command1, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
stdout, stderr = p1.communicate()
print(p1.returncode) #prints -11


  


  stderr of FFmpeg :

  


  ffmpeg version 4.1.3-static https://johnvansickle.com/ffmpeg/  Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 6.3.0 (Debian 6.3.0-18+deb9u1) 20170516
  configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc-6 --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gmp --enable-gray --enable-libaom --enable-libfribidi --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzvbi --enable-libzimg
  libavutil      56. 22.100 / 56. 22.100
  libavcodec     58. 35.100 / 58. 35.100
  libavformat    58. 20.100 / 58. 20.100
  libavdevice    58.  5.100 / 58.  5.100
  libavfilter     7. 40.101 /  7. 40.101
  libswscale      5.  3.100 /  5.  3.100
  libswresample   3.  3.100 /  3.  3.100
  libpostproc    55.  3.100 / 55.  3.100
[tcp @ 0x728cc00] Starting connection attempt to 52.219.74.177 port 443
[tcp @ 0x728cc00] Successfully connected to 52.219.74.177 port 443
[h264 @ 0x729b780] Reinit context to 1280x720, pix_fmt: yuv420p
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'https://bucket.s3.amazonaws.com --> presigned url with 15 min expiration time':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: mp42mp41isomavc1
    creation_time   : 2015-09-02T07:42:42.000000Z
  Duration: 00:00:15.64, start: 0.000000, bitrate: 2640 kb/s
    Stream #0:0(und): Video: h264 (High), 1 reference frame (avc1 / 0x31637661), yuv420p(tv, bt709, left), 1280x720 [SAR 1:1 DAR 16:9], 2475 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc (default)
    Metadata:
      creation_time   : 2015-09-02T07:42:42.000000Z
      handler_name    : L-SMASH Video Handler
      encoder         : AVC Coding
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 160 kb/s (default)
    Metadata:
      creation_time   : 2015-09-02T07:42:42.000000Z
      handler_name    : L-SMASH Audio Handler
[mp3 @ 0x733f340] Skipping 0 bytes of junk at 1344.
Input #1, mp3, from '/opt/bin/audio.mp3':
  Metadata:
    encoded_by      : Logic Pro X
    date            : 2021-01-03
    coding_history  : 
    time_reference  : 158760000
    umid            : 0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000004500F9E4
    encoder         : Lavf58.49.100
  Duration: 00:04:01.21, start: 0.025057, bitrate: 320 kb/s
    Stream #1:0: Audio: mp3, 44100 Hz, stereo, fltp, 320 kb/s
    Metadata:
      encoder         : Lavc58.97
Input #2, png_pipe, from '/opt/bin/watermark.png':
  Duration: N/A, bitrate: N/A
    Stream #2:0: Video: png, 1 reference frame, rgba(pc), 701x190 [SAR 1521:1521 DAR 701:190], 25 tbr, 25 tbn, 25 tbc
[Parsed_scale_0 @ 0x7341140] w:1920 h:1080 flags:'bilinear' interl:0
Stream mapping:
  Stream #0:0 (h264) -> scale
  Stream #2:0 (png) -> overlay:overlay
  format -> Stream #0:0 (libx264)
  Stream #1:0 -> #0:1 (copy)
Press [q] to stop, [?] for help
[h264 @ 0x72d8600] Reinit context to 1280x720, pix_fmt: yuv420p
[Parsed_scale_0 @ 0x733c1c0] w:1920 h:1080 flags:'bilinear' interl:0
[graph 0 input from stream 0:0 @ 0x7669200] w:1280 h:720 pixfmt:yuv420p tb:1/25 fr:25/1 sar:1/1 sws_param:flags=2
[graph 0 input from stream 2:0 @ 0x766a980] w:701 h:190 pixfmt:rgba tb:1/25 fr:25/1 sar:1521/1521 sws_param:flags=2
[auto_scaler_0 @ 0x7670240] w:iw h:ih flags:'bilinear' interl:0
[deinterlace_in_2_0 @ 0x766b680] auto-inserting filter 'auto_scaler_0' between the filter 'graph 0 input from stream 2:0' and the filter 'deinterlace_in_2_0'
[Parsed_scale_0 @ 0x733c1c0] w:1280 h:720 fmt:yuv420p sar:1/1 -> w:1920 h:1080 fmt:yuv420p sar:1/1 flags:0x2
[Parsed_pad_1 @ 0x733ce00] w:1920 h:1080 -> w:1920 h:1080 x:0 y:0 color:0x000000FF
[Parsed_setsar_2 @ 0x733da00] w:1920 h:1080 sar:1/1 dar:16/9 -> sar:1/1 dar:16/9
[auto_scaler_0 @ 0x7670240] w:701 h:190 fmt:rgba sar:1521/1521 -> w:701 h:190 fmt:yuva420p sar:1/1 flags:0x2
[Parsed_overlay_3 @ 0x733e440] main w:1920 h:1080 fmt:yuv420p overlay w:701 h:190 fmt:yuva420p
[Parsed_overlay_3 @ 0x733e440] [framesync @ 0x733e5a8] Selected 1/50 time base
[Parsed_overlay_3 @ 0x733e440] [framesync @ 0x733e5a8] Sync level 2
[libx264 @ 0x72c1c00] using SAR=1/1
[libx264 @ 0x72c1c00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0x72c1c00] profile Progressive High, level 4.0, 4:2:0, 8-bit
[libx264 @ 0x72c1c00] 264 - core 157 r2969 d4099dd - H.264/MPEG-4 AVC codec - Copyleft 2003-2019 - http://www.videolan.org/x264.html - options: cabac=1 ref=1 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=2 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=9 lookahead_threads=3 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=1 keyint=60 keyint_min=6 scenecut=40 intra_refresh=0 rc_lookahead=10 rc=abr mbtree=1 bitrate=4500 ratetol=1.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, flv, to 'pipe:':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: mp42mp41isomavc1
    encoder         : Lavf58.20.100
    Stream #0:0: Video: h264 (libx264), 1 reference frame ([7][0][0][0] / 0x0007), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=-1--1, 4500 kb/s, 30 fps, 1k tbn, 30 tbc (default)
    Metadata:
      encoder         : Lavc58.35.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/4500000 buffer size: 0 vbv_delay: -1
    Stream #0:1: Audio: mp3 ([2][0][0][0] / 0x0002), 44100 Hz, stereo, fltp, 320 kb/s
    Metadata:
      encoder         : Lavc58.97
frame=   27 fps=0.0 q=32.0 size=     247kB time=00:00:00.03 bitrate=59500.0kbits/s speed=0.0672x
frame=   77 fps= 77 q=27.0 size=    1115kB time=00:00:02.03 bitrate=4478.0kbits/s speed=2.03x
frame=  126 fps= 83 q=25.0 size=    2302kB time=00:00:04.00 bitrate=4712.4kbits/s speed=2.64x
frame=  177 fps= 87 q=26.0 size=    3576kB time=00:00:06.03 bitrate=4854.4kbits/s speed=2.97x
frame=  225 fps= 88 q=25.0 size=    4910kB time=00:00:07.96 bitrate=5047.8kbits/s speed=3.13x
frame=  272 fps= 89 q=27.0 size=    6189kB time=00:00:09.84 bitrate=5147.9kbits/s speed=3.22x
frame=  320 fps= 90 q=27.0 size=    7058kB time=00:00:11.78 bitrate=4907.5kbits/s speed=3.31x
frame=  372 fps= 91 q=26.0 size=    8098kB time=00:00:13.84 bitrate=4791.0kbits/s speed=3.4x


  


  And that's the end of it. It should continue to do the processing until 00:04:02 as that's my audio's length but it stops here every time (approximately this is my video length).

  


  The relevant code which works correctly :

  


  ffmpeg_cmd = '/opt/bin/ffmpeg -stream_loop -1 -i "' + '/tmp/' + s3_source_key + '" -i /opt/bin/audio.mp3 -i /opt/bin/watermark.png -shortest -y -deinterlace -vcodec libx264 -pix_fmt yuv420p -preset veryfast -r 30 -g 60 -b:v 4500k -c:a copy -map 0:v:0 -map 1:a:0 -filter_complex scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2,setsar=1,overlay=(W-w)/2:(H-h)/2,format=yuv420p -loglevel verbose -f flv -'
command1 = shlex.split(ffmpeg_cmd)
p1 = subprocess.Popen(command1, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
stdout, stderr = p1.communicate()
print(p1.returncode) #prints 0


  


  With this code it repeats the video as many times as it has to do to be as long as the audio.

  


  Both versions work correctly on my computer.

  


  This question is almost the same but in my case FFmpeg is able to access the signed URL.

  


• Extract frames from a large video c#

  21 janvier 2014, par las

  I am developing a video editing software.
  For that I need to first load a video for editing.
  After loading the video I need to create a timeline of the video with its Thumbnail images which should take in every one seconds.

  I have tried many options for that but still have an issue with more 10 - 15 mins videos.

  First I used ffmpeg.
  There I tired two options.They ended up with following results
   One is very slow
   Another one is fast but thumbnails are not accurate

  Next I used Aforge.Net
   There I can save images to disk but cannot access after 2000-3000 thumbnails
  (It gives out of memory exception)

  Please if you have good suggestion let me know for this task.
  Any one like to see my tried code samples let me know , I will add it to this question.

  Following is the method for reading images which are in the Disk

    void AddThumbnailImages(int i)
  
    {
  
  
  
       PictureBox pictureBox = new PictureBox();
  
       pictureBox.Size = new System.Drawing.Size(100, 75);
  
  
  
        pictureBox.Image = (Bitmap)new Bitmap("Snaps\\" + i + ".jpeg").Clone();
  
  
  
          if (i == totalFrames)
  
        { pictureBox.Tag = totalTimeForFrames; }
  
        else { pictureBox.Tag = (i / frameRate); }
  
        pictureBox.MouseClick += new MouseEventHandler(ViewImageTag);
  
        pictureBox.MouseDoubleClick += new MouseEventHandler(videoCuting);
  
        pictureBox.MouseHover += new EventHandler(pictureBox_MouseHover);
  
        pictureBox.SizeMode = PictureBoxSizeMode.Zoom;
  
        pictureBox.BringToFront();
  
  
  
       pictureBox.Location = new Point(pictureBoxlocationX + (100 * (i/frameRate)),         pictureBoxlocationY);
  
       panelTimeline.Controls.Add(pictureBox);
  
  
  
     }