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• From multiple video files to single output

  25 juillet 2019, par Cordo van Saviour

  Let’s say that I have a list of hundreds of possible video files. Using ffmpeg it’s pretty easy to take multiple files and stitch them together to single video output, but that’s where the things become tricky.

  I’m looking for a way to have them stream live and dynamically add videos to queue as stream goes on. Think of something like SSAI but for the whole video.

  Stream live is there so we don’t have a delay while waiting for ffmpeg to finish the whole video but rather start as soon as possible, and also so we could choose next files in queue during the live stream.

  Simplified, it would look something like this :

  [v] [v] [v] [v] - stored video files, eg. on S3 
  
  
  
        [v] - chosen file
  
  
  
        | | 
  
        | | - during the live stream
  
        | |
  
        \ /
  
         V    
  
     _________             ___________              ___________
  
     \       /             |         |              ||       ||
  
      \     /    =====>    |         |    =====>    ||  |:>  ||
  
       \___/               |_________|              ||_______||
  
    Video queue              FFMPEG?                Live stream
  
                        Transcoding module?
  
                              Magic?

  I’m writing this in Node.js if that makes any difference.

  Is this even possible ? If you need any more information please ask away, and every suggestion is greatly appreciated !

• avcodec/agm : Fix integer overflow with w/h

  5 avril 2019, par Michael Niedermayer

  avcodec/agm : Fix integer overflow with w/h
  Fixes : negation of -2147483648 cannot be represented in type 'int' ; cast to an unsigned type to negate this value to itself
  
  Fixes : 13999/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_AGM_fuzzer-5644405991538688
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
  
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/agm.c

• Convert YUV420 to BGR without using videoconvert in GStreamer

  23 septembre 2019, par AnD Max

  I am using GSteamer, and I want to convert I420 to BGR format.
  Pipeline :

  gst-launch-1.0 filesrc location= ./Big_Buck_Bunny_1080_10s_1MB.mp4 ! qtdemux ! h264parse ! avdec_h264 ! fakesink

  I don’t use videoconvert plugin because it takes many CPU workload.
  I saw that avdec_h264 plugins has support BGR format and I tried to chose BGR format but the output always give I420 format ("avdec_h264 ! video/x-raw, format=BGR !").

  I tried to cast it to BGR format in source code (gst-libav/ext/libav/gstavvidec.c\gst_ffmpeg_pixfmt_to_videoformat()) but I got an error in (gst-libav/gst-libs/ext/libav/libavcodec/decode.c), 1606

  for (i = 0; i < num_planes; i++) {
  
              av_assert0(frame->data[i]);
  
          }

  Does my way correct ? Should I modify num_planes in deocode.c ?
  If it’s not a right way, can I convert format by using OpenCV with GStreamer pipeline ?

  If you have any good way, please tell me also.