• Compression Techniques

  Trying to screencast, refuses with scene change error?

  Posted by Lugo Teehalt on August 2, 2011 at 9:15 am

  [CODE]ffmpeg -f alsa -ac 2 -i pulse -f x11grab -r 30 -s 1024×768 -i :0.0 -acodec pcm_s16le -fpre /usr/local/share/ffmpeg/libx264-lossless_ultrafast.ffpreset -threads 0 output.mkv
  ffmpeg version N-31720-g03cbe6c, Copyright (c) 2000-2011 the FFmpeg developers
  built on Aug 2 2011 08:46:29 with gcc 4.4.5
  configuration: –enable-gpl –enable-libfaac –enable-libmp3lame –enable-libopencore-amrnb –enable-libopencore-amrwb –enable-libtheora –enable-libvorbis –enable-libx264 –enable-libxvid –enable-nonfree –enable-postproc –enable-version3 –enable-x11grab –enable-libvpx
  libavutil 51. 11. 1 / 51. 11. 1
  libavcodec 53. 9. 0 / 53. 9. 0
  libavformat 53. 6. 0 / 53. 6. 0
  libavdevice 53. 2. 0 / 53. 2. 0
  libavfilter 2. 27. 5 / 2. 27. 5
  libswscale 2. 0. 0 / 2. 0. 0
  libpostproc 51. 2. 0 / 51. 2. 0
  [alsa @ 0x94ab3a0] Estimating duration from bitrate, this may be inaccurate
  Input #0, alsa, from ‘pulse’:
  Duration: N/A, start: 1312272653.688062, bitrate: N/A
  Stream #0.0: Audio: pcm_s16le, 48000 Hz, 2 channels, s16, 1536 kb/s
  [x11grab @ 0x94acec0] device: :0.0 -> display: :0.0 x: 0 y: 0 width: 1024 height: 768
  [x11grab @ 0x94acec0] shared memory extension found
  [x11grab @ 0x94acec0] Estimating duration from bitrate, this may be inaccurate
  Input #1, x11grab, from ‘:0.0’:
  Duration: N/A, start: 1312272653.741166, bitrate: 754974 kb/s
  Stream #1.0: Video: rawvideo, bgra, 1024×768, 754974 kb/s, 30 tbr, 1000k tbn, 30 tbc
  File ‘output.mkv’ already exists. Overwrite ? [y/N] y
  Incompatible pixel format ‘bgra’ for codec ‘mpeg4’, auto-selecting format ‘yuv420p’
  [buffer @ 0x94a5c80] w:1024 h:768 pixfmt:bgra tb:1/1000000 sar:0/1 sws_param:
  [buffersink @ 0x94c16e0] auto-inserting filter ‘auto-inserted scaler 0’ between the filter ‘src’ and the filter ‘out’
  [scale @ 0x94c36e0] w:1024 h:768 fmt:bgra -> w:1024 h:768 fmt:yuv420p flags:0x4
  [mpeg4 @ 0x94bf1c0] closed gop with scene change detection are not supported yet, set threshold to 1000000000
  Output #0, matroska, to ‘output.mkv’:
  Stream #0.0: Video: mpeg4, yuv420p, 1024×768, q=0-69, 200 kb/s, 90k tbn, 30 tbc
  Stream #0.1: Audio: pcm_s16le, 48000 Hz, 2 channels, s16, 1536 kb/s
  Stream mapping:
  Stream #1.0 -> #0.0
  Stream #0.0 -> #0.1
  Error while opening encoder for output stream #0.0 – maybe incorrect parameters such as bit_rate, rate, width or height
  lugo@debian:~$
  [/CODE]

  [mpeg4 @ 0x94bf1c0] closed gop with scene change detection are not supported yet, set threshold to 1000000000
  is in red.

  Tried putting in: -sc_threshold 100000000 -flags +cgop and variations of this but it only changed the thing in the square brackets at the start of the red message. Also fiddled with bitrate etc. parameters.

  Great thanks any help.

  Lugo Teehalt replied 15 years, 1 month ago 1 Member · 0 Replies
• 0 Replies

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