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• FFmpeg raw video size parameter

  3 novembre 2019, par Yanick Salzmann

  I am using libavformat in my library to read a stream of raw i420 images and transform them into an mp4 video. I’ve found CLI commands that perform this but since I am using the library in my program I need to reconstruct the same thing.

  Currently the code that is having a problem is looking like this :

          const auto raw_format = av_find_input_format("rawvideo");
  
          if (raw_format == nullptr) {
  
              log->error("Could not find RAW input parser in FFmpeg");
  
              throw std::runtime_error("RAW not found");
  
          }
  
  
  
          _format_context->pb = _io_context.get();
  
  
  
          AVDictionary *input_options = nullptr;
  
          av_dict_set(&input_options, "framerate", std::to_string(fps).c_str(), 0);
  
          av_dict_set(&input_options, "pix_fmt", "yuv420p", 0);
  
          av_dict_set(&input_options, "s:v", fmt::format("{}x{}", width, height).c_str(), 0);
  
          av_dict_set(&input_options, "size", fmt::format("{}x{}", width, height).c_str(), 0);
  
  
  
          auto formatPtr = _format_context.get();
  
          auto res = avformat_open_input(&formatPtr, "(memory file)", raw_format, &input_options);

  Finding the rawvideo is no problem, but it fails in avformat_open_input with the error : [2019-11-03 15:03:22.953] [11599:11663] [ffmpeg] [error] Picture size 0x0 is invalid

  I assumed the sizes are something I can insert using the input options, since in the CLI version it is passed using -s:v 1920x1080, however this does not seem to be true.

  Where do I have to specify the dimensions of my raw input stream ?

• ffmpeg : precisely cut a video

  19 octobre 2019, par Santhosh Yedidi

  I am tring to cut a video in linux OS

  $ ffmpeg -i dhol.mkv 
  
  ffmpeg version n4.1.2 Copyright (c) 2000-2019 the FFmpeg developers
  
    built with gcc 8.2.1 (GCC) 20181127
  
    configuration: --prefix=/usr --disable-debug --disable-static --disable-stripping --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libdrm --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libiec61883 --enable-libjack --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxml2 --enable-libxvid --enable-nvdec --enable-nvenc --enable-omx --enable-shared --enable-version3
  
    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
  
  Input #0, matroska,webm, from 'dhol.mkv':
  
    Metadata:
  
      ENCODER         : Lavf58.20.100
  
    Duration: 00:03:56.18, start: -0.007000, bitrate: 2688 kb/s
  
      Stream #0:0(eng): Video: vp9 (Profile 0), yuv420p(tv, bt709/unknown/unknown), 1920x1080, SAR 1:1 DAR 16:9, 30 fps, 30 tbr, 1k tbn, 1k tbc (default)
  
      Metadata:
  
        DURATION        : 00:03:56.167000000
  
      Stream #0:1(eng): Audio: opus, 48000 Hz, stereo, fltp (default)
  
      Metadata:
  
        DURATION        : 00:03:56.181000000

  I was trying to precisely cut the video file :

  But using ffmpeg I was not successfull. It cuts from the nearest key frames to the given start time

  ffmpeg -y -i dhol.mkv -ss $shift   -t $duration -c:v copy -an output.mkv

  ONE OF THE REASONS HERE IS H.264 Video format (YUV420p vs YUV420sp). I am using -c:v copy so it has to use the same format YUV420p, so it has to start from nearest keyframe

  Now the only reliable software that i can fully depend if avidemux.

  Even in that i have to select

  video-codec: MJPEG
  
  audio-codec: vorbis

  But the cut video size will be large.

  I tried in avidemux

  video-codec: copy
  
  audio-codec: copy

  It will cut from nearest keyframe than precisely.

  One conclusion :
  So irrespective of ffmpeg or avidemux, the output video format yuv420p will not allow precise formatting

  Only option currently possible :

  Using avidemux and with

  video-codec: MJPEG
  
  audio-codec: vorbis

  Cons :

  1) bigger video size.
  
  2) no proper command line examples available for avidemux to do the same as gui does

  I tried command line in avidemux :

  avidemux3_cli --video-codec MJPEG --audio-codec AAC --output-format AVI --load dhol.mkv --begin 137.633 --end 141.334 --save dhol2.mkv

  It tries to convert the whole file rather than from the start to end time

  My requirement :
  I want to do it command line.

  I didnt try with ffmpeg (with video codec : MJPEG and audio : vorbis). I never saw any example

  How to precisely cut a video (even the output format can be different (like MJPEG instead of yuv420p, and also bigger sizes, its ok) using command line

• ffmpeg faild when processing video from stream

  17 octobre 2019, par Milousel

  I create ffmpeg method for modify video from readstream as input. I test it on videos which I download from internet and it’s works good. When I tried it on video from my phone it crash. I tried to modify (take off few second) video from internet and try it again, but I receive the same error message.

   an error happened: ffmpeg exited with code 1: pipe:0: Invalid data found when processing input
  
  Cannot determine format of input stream 0:0 after EOF
  
  Error marking filters as finished
  
  Conversion failed!
  
  ffmpeg version N-92722-gf22fcd4483 Copyright (c) 2000-2018 the FFmpeg developers
  
    built with gcc 8.2.1 (GCC) 20181201
  
    configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt
  
    libavutil      56. 24.101 / 56. 24.101
  
    libavcodec     58. 42.102 / 58. 42.102
  
    libavformat    58. 24.101 / 58. 24.101
  
    libavdevice    58.  6.101 / 58.  6.101
  
    libavfilter     7. 46.101 /  7. 46.101
  
    libswscale      5.  4.100 /  5.  4.100
  
    libswresample   3.  4.100 /  3.  4.100
  
    libpostproc    55.  4.100 / 55.  4.100
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 000001c49b5ee3c0] stream 0, offset 0x20: partial file
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 000001c49b5ee3c0] Could not find codec parameters for stream 0 (Video: h264 (avc1 / 0x31637661), none(tv, bt709), 1920x1080, 17079 kb/s): unspecified pixel format
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'pipe:0':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: isommp42
  
      creation_time   : 2019-10-17T11:32:34.000000Z
  
      location        : +50.1308+014.3730/
  
      location-eng    : +50.1308+014.3730/
  
      com.android.version: 7.0
  
    Duration: 00:00:10.77, start: 0.000000, bitrate: N/A
  
      Stream #0:0(eng): Video: h264 (avc1 / 0x31637661), none(tv, bt709), 1920x1080, 17079 kb/s, SAR 1:1 DAR 16:9, 30 fps, 30 tbr, 90k tbn, 180k tbc (default)
  
      Metadata:
  
        rotate          : 90
  
        creation_time   : 2019-10-17T11:32:34.000000Z
  
        handler_name    : VideoHandle
  
      Side data:
  
        displaymatrix: rotation of -90.00 degrees
  
      Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 127 kb/s (default)
  
      Metadata:
  
        creation_time   : 2019-10-17T11:32:34.000000Z
  
        handler_name    : SoundHandle
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  
    Stream #0:1 -> #0:1 (aac (native) -> mp3 (libmp3lame))
  
    Stream #0:0 -> #1:0 (h264 (native) -> mjpeg (native))
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 000001c49b5ee3c0] stream 0, offset 0x20: partial file
  
  pipe:0: Invalid data found when processing input
  
  Cannot determine format of input stream 0:0 after EOF
  
  Error marking filters as finished
  
  Conversion failed!

  ffmpeg(stream)
  
          .outputOptions('-movflags', 'faststart')
  
         // .size('1320x438')
  
          .videoCodec('libx264')
  
          .toFormat('avi')
  
          .output(fileName)
  
          .on('error', function(err: { message: string; }, stdout: any, stderr: any) {
  
            console.log('an error happened: ' + err.message + stdout + stderr);
  
           })
  
          .on('end', function() {
  
            console.log('Finished processing video');
  
            const params = {
  
              Body: fs.createReadStream(fileName),
  
              Bucket: videoBucket,
  
              Key: 'test/modification/' + fileName,
  
            };
  
            s3.putObject(params, (err, data) => {
  
              if (err) {
  
                console.log(err);
  
              }
  
            });
  
          })
  
          .output(screensName + '.jpg')
  
          .outputOptions(
  
            '-frames',
  
            '1', // Capture just one frame of the video
  
            '-vf',
  
            'blackdetect=d=2:pix_th=0.00',
  
          )
  
          .on('end', function() {
  
            console.log('Finished processing screenshot');
  
            const params = {
  
              Body: fs.createReadStream(screensName + '.jpg'),
  
              Bucket: videoBucket,
  
              Key: 'test/shots/' + screensName + '.jpg',
  
            };
  
            s3.putObject(params, (err, data) => {
  
              if (err) {
  
                console.log(err);
  
              }
  
            });
  
          })
  
          .run();