Newest 'ffmpeg' Questions - Stack Overflow

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• ffmpeg - how do I remove a sweep line seen

  8 novembre 2013, par eduard

  I am streaming a video over network(rtp) which uses x264 and ffmpeg's h264 on the other side. Everything is OK as far as there is no packet loss. When there are packet loss it fixed when key-frame arives. Instead of immediate refresh it takes about 1-1.5 seconds and it seems like a sweep line which 'cleans' the errors.

  Is there a way to make key frames fix errors immediately?

• Make thumbs from videos with ffmpeg and php [on hold]

  8 novembre 2013, par Milan Milosevic

  Im try extract small thumbs from video every 15 sec.

  Here is what im try now

  ffmpeg -i movie.mp4 -r 1/15 -s 120x90 %03d.jpg
  

  But have some error from command line

  [mjpeg @ 0x9e695c0] bitrate tolerance too small for bitrate
  [mjpeg @ 0x9da9a60] ff_frame_thread_encoder_init failed
  Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height
  

  Whats wrong here, and how to get thumbs every 15 sec. and save it 0.jpg,1jpg,2jpg,3jpg,4jpg,5jpg...etc..

• FFmpeg 1.0 causing audio playback issues

  7 novembre 2013, par Jona

  I have an audio streamer based on ffplay. It works great using ffmpeg 0.11 but when I use ffmpeg 1.0 or the latest 1.2 release the audio seems to be decoded or played weirdly.

  Essentially it sounds like chipmunks with mp3 streams and with aac streams I hear tons of static barely hearing the actual stream and the actual stream sounds slow.

  Any ideas the possible changes in ffmpeg that could have caused these types of issues?

  Similar issue was posted here but no actual answer about what is going on. Supposedly this code reproduces the same issue.

  UPDATE 1:
  I have done a step by step copy from ffplay and still no luck! :/ The channel and sampling rate look correct so there must be something internally that is returning a weird decoded format?

• Lossless video codec squashing dim pixels using avconv

  7 novembre 2013, par Noah

  I am using avconv to convert a raw avi grayscale video to huffyuv with mkv container. I've read that huffyuv is "mathematically lossless", which is precisely what I want. avoprobe on the input file gives

  Input #0, avi, from 'myvid.avi':   Duration: 00:00:32.94, start: 0.000000, bitrate: 129167 kb/s
      Stream #0.0: Video: rawvideo, pal8, 328x246, 200 fps, 0.08 tbr, 200 tbn, 200 tbc
  

  The movie has high intensity (approx 150-250 in 8 bits) and low intensity (1-9) elements that I would like to preserve. However if I run

  avconv -y -an -i myvid.avi -r 200 -c:v huffyuv av_test.mkv
  

  I get a text.mkv where the low intensity details have vanished. In fact I was able to plot the following for the two videos.

  So avconv is deciding I don't need those critical dim pixels. I could just add, say, 15 to all pixel values, but then I would saturate my bright pixels and there's no guarantee the cutoff value is the same for all videos. I do some downstream processing on the output where I really need pixel values to not change when I convert video formats. Any insights as to how to get avconv or huffyuv to actually save my video without loss?

• ffmpeg : save separate frames as still gifs

  7 novembre 2013, par Eugene M

  The question is simple: I don't want ffmpeg to create an animated GIF from given video stream, I want separate frames, each in GIF format. But when I set output file to something like frame%09d.gif ffmpeg tends to create an animation (and stores it exactly as frame%09d.gif). The same for -f gif option.

  Of course, I could save PNGs and use ImageMagic's convert utility to transform them to GIFs, but I don't want any additional invocation overhead because I'm dealing with live streams and going to crunch large amounts of data.

  Here is what I do, nothing special:

  ffmpeg -i http://brightcove03-f.akamaihd.net/valgbodmandag1378107345_1_300k@80362 -f gif -y frame_%09d.gif
  
  ffmpeg version N-54643-g15cee5e Copyright (c) 2000-2013 the FFmpeg developers
    built on Jul 11 2013 03:35:11 with gcc 4.7.3 (GCC)
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnu
  tls --enable-iconv --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetype --enable-libgsm --enable-libilbc --enable-libmodplug --ena
  ble-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger -
  -enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-lib
  vpx --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
    libavutil      52. 39.100 / 52. 39.100
    libavcodec     55. 18.102 / 55. 18.102
    libavformat    55. 12.101 / 55. 12.101
    libavdevice    55.  3.100 / 55.  3.100
    libavfilter     3. 80.100 /  3. 80.100
    libswscale      2.  3.100 /  2.  3.100
    libswresample   0. 17.102 /  0. 17.102
    libpostproc    52.  3.100 / 52.  3.100
  [flv @ 00000000002cb700] Stream discovered after head already parsed
  Input #0, flv, from 'http://brightcove03-f.akamaihd.net/valgbodmandag1378107345_1_300k@80362':
    Metadata:
      encoder         : Lavf54.6.100
    Duration: 00:00:00.00, start: 0.000000, bitrate: N/A
      Stream #0:0: Video: h264 (Constrained Baseline), yuv420p, 480x270 [SAR 1:1 DAR 16:9], 25 tbr, 1k tbn, 50 tbc
      Stream #0:1: Audio: aac, 44100 Hz, stereo, fltp, 128 kb/s
      Stream #0:2: Data: none
  [swscaler @ 0000000004d051e0] No accelerated colorspace conversion found from yuv420p to bgr8.
  Output #0, gif, to 'frame_%09d.gif':
    Metadata:
      encoder         : Lavf55.12.101
      Stream #0:0: Video: gif, bgr8, 480x270 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 100 tbn, 25 tbc
  Stream mapping:
    Stream #0:0 -> #0:0 (h264 -> gif)
  Press [q] to stop, [?] for help
  frame=  141 fps=130 q=-1.0 Lsize=    4960kB time=00:00:05.68 bitrate=7153.1kbits/s
  video:5100kB audio:0kB subtitle:0 global headers:0kB muxing overhead -2.743247%
  

  After all I get a file named "frame_%03d.gif", but instead I want to have several files "frame_001.gif", "frame_002.gif", etc.

  Any ideas? Thanks in advance.