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• What is substitute for ffmpeg video filter "between" for audio filter

  18 janvier 2018, par Hekimen

  i want make a short video preview from long video with audio, but i have problem to select audio stream segments on specific timestamps.
  I am using this option for segmenting video

  -filter_complex "[0:v]select='between(t,216,220.5)+between(t,432,436.5)+between(t,648,652.5)+between(t,864,868.5)+between(t,1080,1084.5)+between(t,1296,1300.5)+between(t,1512,1516.5)+between(t,1728,1732.5)+between(t,1944,1948.5)+between(t,2160,2164.5)'[outv]"

  and my question is how this option rewrite for audio stream, because when i use just -filter without selecting any stream then i get error : Cannot connect video filter to audio input

  I am using this ffmpeg version :

  ffmpeg version 3.3.3-static http://johnvansickle.com/ffmpeg/  Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 6.4.0 (Debian 6.4.0-2) 20170724
  configuration : —enable-gpl —enable-version3 —enable-static —disable-debug —disable-ffplay —disable-indev=sndio —disable-outdev=sndio —cc=gcc-6 —enable-fontconfig —enable-frei0r —e
  nable-gnutls —enable-gray —enable-libass —enable-libfreetype —enable-libfribidi —enable-libmp3lame —enable-libopencore-amrnb —enable-libopencore-amrwb —enable-libopus —enable-librtm
  p —enable-libsoxr —enable-libspeex —enable-libtheora —enable-libvidstab —enable-libvo-amrwbenc —enable-libvorbis —enable-libvpx —enable-libwebp —enable-libx264 —enable-libxvid
  libavutil      55. 58.100 / 55. 58.100
  libavcodec     57. 89.100 / 57. 89.100
  libavformat    57. 71.100 / 57. 71.100
  libavdevice    57.  6.100 / 57.  6.100
  libavfilter     6. 82.100 /  6. 82.100
  libswscale      4.  6.100 /  4.  6.100
  libswresample   2.  7.100 /  2.  7.100
  libpostproc    54.  5.100 / 54.  5.100
  

• ffmpeg dash Segment offset

  18 mars 2019, par inkubux

  I’m trying to integrate live-transcoding like "plex" or "emby" with my application.

  I am able to serve dash content over to shaka-player or dash.js but only in ’live-mode’. But I want to enable seeking through the player.

  I looked at plex and to enable this they create their own mpd file with duration so the player will have a full seekbar.

  However when seeking the player will ask for a segment number eg : 449. I need to stop ffmpeg and restart with an offset (-ss &lt;<segment>>)</segment>, but ffmpeg will just restart a transcode session from segment 0 with an initial segment.

  What I want is to tell ffmpeg to start at a seekpoint but only output from segment number and now-on.

  When playing with hls and mpegts, I can tell ffmpeg to output at a certain segment : with the option -segment_start_number but this is not available for dash. And plex use their own transcoder based of ffmpeg with the option -skip_to_segment

  I tried to ’hack’ around by keeping a manual offset on my web-server, even if I serve the "supposed" right segment after the seek point dash.js and shaka-player can’t recover the stream.. VLC on the other habd is able to (probably more tolerent) to errors in segments.

  Is the supposed right segment after a seek in dash (contains the initial segment) or only the segment.

  Is ffmpeg able to start segmenting dash as a supposed segment (for seek and resume)

  The same technique works in hls with forced key frames and a custom m3u8 (with all the "predicted" segments) but calculating the right segment length and the right bandwidth is much harder and hackish and dash is more tolerant to variation.

  I would really like to be able to seek through my live transcoding video.

  For reference here is a custom mpd file I serve to enable "seeking" :

  <mpd xmlns="urn:mpeg:dash:schema:mpd:2011" profiles="urn:mpeg:dash:profile:isoff-live:2011" type="static" suggestedpresentationdelay="PT1S" mediapresentationduration="PT49M2.920S" maxsegmentduration="PT2S" minbuffertime="PT10S">
  
      <period start="PT0S" duration="PT49M2.920S">
  
          <adaptationset segmentalignment="true">
  
              <segmenttemplate timescale="1" duration="1" initialization="$RepresentationID$/initial.mp4" media="$RepresentationID$/$Number$.m4s" startnumber="1">
  
              </segmenttemplate>
  
              <representation mimetype="video/mp4" codecs="avc1.640029" bandwidth="3766000" width="1920" height="1080">
  
              </representation>
  
          </adaptationset>
  
          <adaptationset segmentalignment="true">
  
              <segmenttemplate timescale="1" duration="1" initialization="$RepresentationID$/initial.mp4" media="$RepresentationID$/$Number$.m4s" startnumber="1">
  
              </segmenttemplate>
  
              <representation mimetype="audio/mp4" codecs="mp4a.40.2" bandwidth="188000" audiosamplingrate="48000">
  
                  <audiochannelconfiguration schemeiduri="urn:mpeg:dash:23003:3:audio_channel_configuration:2011" value="6"></audiochannelconfiguration>
  
              </representation>
  
          </adaptationset>
  
      </period>
  
  </mpd>

  And here is the ffmpeg command to pull it off :

  ffmpeg -ss 0 -i movie.mkv -y -acodec aac -vcodec libx264 -f dash -min_seg_duration 1000000 -individual_header_trailer 0 -pix_fmt yuv420p -vf scale=trunc(min(max(iw\,ih*dar)\,1920)/2)*2:trunc(ow/dar/2)*2 -bsf:v h264_mp4toannexb -profile:v high -level 4.1 -map_chapters -1 -map_metadata -1 -preset veryfast -movflags frag_keyframe+empty_moov -use_template 1 -use_timeline 0 -remove_at_exit 1 -crf 23 -bufsize 7532k -maxrate 3766k -start_at_zero -threads 0 -force_key_frames expr:if(isnan(prev_forced_t),eq(t,t),gte(t,prev_forced_t+1)) -init_seg_name $RepresentationID$/0_initial.mp4 -media_seg_name $RepresentationID$/0_$Number$.m4s /transcoding_temp/Z1GVWEc/index.mpd

  The media_seg_name is where I prepend the custom seek_point let’s say I want to seek to segment 1233 the template would be :

  -media_seg_name $RepresentationID$/1233_$Number$.m4s

  and the segments would be 1233_1 1233_2 1233_* So I can serve the right segment after seek. but the player does not recover and still downloading subsequent segments. I guess since a new initial segment is generated and I somehow miss headers for continuous playback after seek but I’m probably wrong.

  Thanks for your help

• ffmpeg generate thumbnails on GPU

  22 juin 2018, par Oleksandr Kyrpa

  I try to generate thumbnails with acceleration on GPU, so compile ffmpeg 3.4.1 and run command :

  ./ffmpeg  -i ~/Videos/1080.mp4 -vf "hwupload_cuda,thumbnail_cuda=100,scale_cuda=107:60,hwdownload,format=yuv420p" -vframes 1 -y ~/Videos/thumbs/thumb%03d.jpg

  But I get wrong output picture (the color of thumbnail is green) :

  

  Correct image must be black.
  How to make first image with correct color ?

  

  log : -loglevel verbose

  ffmpeg version N-89707-g89b84cb Copyright (c) 2000-2018 the FFmpeg developers
  
    built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04.3)
  
    configuration: --cpu=native --enable-pthreads --extra-version=hd --enable-gnutls --enable-vaapi --enable-vdpau --enable-nonfree --enable-gpl --enable-swscale --enable-libx264 --enable-version3 --enable-nvenc --enable-libnpp --enable-cuda --enable-cuvid --enable-cuda-sdk --enable-filter=scale_cuda --enable-filter=thumbnail_cuda --extra-cflags=-I/usr/local/cuda-8.0/include --extra-ldflags=-L/usr/local/cuda-8.0/lib64
  
    libavutil      56.  7.100 / 56.  7.100
  
    libavcodec     58.  9.100 / 58.  9.100
  
    libavformat    58.  3.100 / 58.  3.100
  
    libavdevice    58.  0.100 / 58.  0.100
  
    libavfilter     7. 11.100 /  7. 11.100
  
    libswscale      5.  0.101 /  5.  0.101
  
    libswresample   3.  0.101 /  3.  0.101
  
    libpostproc    55.  0.100 / 55.  0.100
  
  [h264 @ 0x392ed40] Reinit context to 1920x1088, pix_fmt: yuv420p
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/home/alex/Videos/1080.mp4':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: isommp42
  
      creation_time   : 2012-05-30T20:01:34.000000Z
  
    Duration: 00:01:14.21, start: 0.000000, bitrate: 5476 kb/s
  
      Stream #0:0(und): Video: h264 (High), 1 reference frame (avc1 / 0x31637661), yuv420p(left), 1920x1080 (1920x1088), 5321 kb/s, 29.97 fps, 29.97 tbr, 60k tbn, 59.94 tbc (default)
  
      Metadata:
  
        creation_time   : 1970-01-01T00:00:00.000000Z
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 152 kb/s (default)
  
      Metadata:
  
        creation_time   : 2012-05-30T20:01:34.000000Z
  
        handler_name    : IsoMedia File Produced by Google, 5-11-2011
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (h264 (native) -> mjpeg (native))
  
  Press [q] to stop, [?] for help
  
  [h264 @ 0x3a38280] Reinit context to 1920x1088, pix_fmt: yuv420p
  
  [Parsed_thumbnail_cuda_1 @ 0x4e3d8c0] batch size: 100 frames
  
  [graph 0 input from stream 0:0 @ 0x4e8b640] w:1920 h:1080 pixfmt:yuv420p tb:1/60000 fr:30000/1001 sar:0/1 sws_param:flags=2
  
  [auto_scaler_0 @ 0x4e8ca00] w:iw h:ih flags:'bicubic' interl:0
  
  [format @ 0x4e8b540] auto-inserting filter 'auto_scaler_0' between the filter 'Parsed_format_4' and the filter 'format'
  
  [Parsed_scale_cuda_2 @ 0x4e89380] w:1920 h:1080 -> w:107 h:60
  
  [swscaler @ 0x4ebf0c0] deprecated pixel format used, make sure you did set range correctly
  
  [auto_scaler_0 @ 0x4e8ca00] w:107 h:60 fmt:yuv420p sar:0/1 -> w:107 h:60 fmt:yuvj420p sar:0/1 flags:0x4
  
  Output #0, image2, to '/home/alex/Videos/thumbs/thumb%03d.jpg':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: isommp42
  
      encoder         : Lavf58.3.100
  
      Stream #0:0(und): Video: mjpeg, 1 reference frame, yuvj420p(pc, left), 107x60, q=2-31, 200 kb/s, 29.97 fps, 29.97 tbn, 29.97 tbc (default)
  
      Metadata:
  
        creation_time   : 1970-01-01T00:00:00.000000Z
  
        handler_name    : VideoHandler
  
        encoder         : Lavc58.9.100 mjpeg
  
      Side data:
  
        cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
  
  [Parsed_thumbnail_cuda_1 @ 0x4e3d8c0] frame id #76 (pts_time=2.535867) selected from a set of 100 images
  
  No more output streams to write to, finishing.
  
  frame=    1 fps=0.9 q=3.1 Lsize=N/A time=00:00:02.56 bitrate=N/A speed=2.26x    
  
  video:2kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
  
  Input file #0 (/home/alex/Videos/1080.mp4):
  
    Input stream #0:0 (video): 115 packets read (134655 bytes); 101 frames decoded; 
  
    Input stream #0:1 (audio): 1 packets read (9 bytes); 
  
    Total: 116 packets (134664 bytes) demuxed
  
  Output file #0 (/home/alex/Videos/thumbs/thumb%03d.jpg):
  
    Output stream #0:0 (video): 1 frames encoded; 1 packets muxed (1864 bytes); 
  
    Total: 1 packets (1864 bytes) muxed

  UPDATE, working !
  Add format=nv12 before hwupload

  -vf "format=nv12,hwupload_cuda,thumbnail_cuda,scale_cuda=1280:72‌​0,hwdownload,format=‌​nv12"