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• Merge/Blend/Composite transparent webm files with a jpg/png using ffmpeg

  13 avril 2021, par Lokanath

  I previously had generated color.webm and alpha.webm files withffmpeg using png images.
However, when I play the generated videos in my application it consumes quite some resources so I have decided to create a standard video(No alpha needed), I cannot re-record the videos as there are a lot of them at this point.

  


  I am generating the alpha and color video using the following command ffmpeg -framerate 30 -i img%d.png -filter_complex "alphaextract[a]" -map 0:v -c:v libvpx-vp9 -pix_fmt yuv420p -auto-alt-ref 0 -crf 15 -b:v 0 color.webm -map "[a]" -c:v libvpx-vp9 -pix_fmt yuv420p -auto-alt-ref 0 -crf 15 -b:v 0 alpha.webm

  


  I am looking to get a final video output where in alpha values are replaced with the png/jpg image, it's more like replacing the green screen with a background however in my case greenscreen is the alpha channel.

  


  Could any one let me know how to combine alpha.webm, color.webm with a jpg/png image without minimal or no quality loss ?
.

  


• ffmpeg stream_loop CPU 100%

  20 avril 2020, par beamercola

  I have a pretty simple stream_loop running out to an rtmp server. I even tried to optimize the files so it didn't have to encode but I must be doing something wrong

  



  Here's my code :

  



  play.sh

  



  ffmpeg \
  -stream_loop -1 \
  -i playlist1.txt \
  -c:v copy \
  -c:a copy \
  -f flv "rtmp://..."


  



  playlist1.txt

  



  ffconcat version 1.0
file 'tracks/001.mp4'
file 'playlist2.txt'


  



  playlist2.txt

  



  ffconcat version 1.0
file 'tracks/002.mp4'
file 'playlist1.txt'


  



  I have it in 2 playlists to make it infinite, read that somewhere.

  



  I get a constant log of this
Auto-inserting h264_mp4toannexb bitstream

  



  Here's my output :

  



  ffmpeg version 4.2.2-1ubuntu1~18.04.york0 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 7 (Ubuntu 7.5.0-3ubuntu1~18.04)
  configuration: --prefix=/usr --extra-version='1ubuntu1~18.04.york0' --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x55c005b43700] Auto-inserting h264_mp4toannexb bitstream filter
Input #0, concat, from 'playlist1.txt':
  Duration: N/A, start: 0.000000, bitrate: 406 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 278 kb/s, 10 fps, 10 tbr, 10240 tbn, 20 tbc
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 127 kb/s
    Metadata:
      handler_name    : SoundHandler
Output #0, flv, to 'rtmp://......':
  Metadata:
    encoder         : Lavf58.29.100
    Stream #0:0(und): Video: h264 (High) ([7][0][0][0] / 0x0007), yuv420p, 640x360, q=2-31, 278 kb/s, 10 fps, 10 tbr, 1k tbn, 10240 tbc
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) ([10][0][0][0] / 0x000A), 44100 Hz, stereo, fltp, 127 kb/s
    Metadata:
      handler_name    : SoundHandler
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (copy)
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x55c005bca200] Auto-inserting h264_mp4toannexb bitstream filter34x    
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x55c005c94480] Auto-inserting h264_mp4toannexb bitstream filter03x    
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x55c005bcd7c0] Auto-inserting h264_mp4toannexb bitstream filter91x    
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x55c005bcb780] Auto-inserting h264_mp4toannexb bitstream filter80x    
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x55c005b4ca00] Auto-inserting h264_mp4toannexb bitstream filter78x    
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x55c005b4c900] Auto-inserting h264_mp4toannexb bitstream filter83x    
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x55c005bcba40] Auto-inserting h264_mp4toannexb bitstream filter84x    


  



  my guess is these video files are 1:1. I tried re-encoding to force them to 10fps, but i notice 278 kb/s and 77 kb/s

  



  Any help appreciated thanks !

  


• Copying a FFMPEG AVFrame to a buffer for use with SDL

  13 août 2021, par ryan

  for the past couple of days I've been trying to get a decoded AVFrame* converted to an SDL_Surface. In order to do that, I need to get the pure RGBA data from the frame. Here is the code involved with copying.

  


   std::uint32_t numBytes = av_image_get_buffer_size(AV_PIX_FMT_BGR32,
                                                   codecCtx->width,
                                                   codecCtx->height,
                                                   32);
/// ...
std::vector nBuf(numBytes);
auto e = av_image_copy_to_buffer(nBuf.data(), nBuf.size(),
                                 rgbFrame->data, rgbFrame->linesize,
                                 AV_PIX_FMT_BGR32, codecCtx->width,
                                 codecCtx->height, 32);
auto surf = SDL_CreateRGBSurfaceFrom(reinterpret_cast(nBuf.data()),
                                     codecCtx->width, codecCtx->height,
                                     32, 4 * codecCtx->width, 0x000000FF, 0x0000FF00,
                                     0x00FF0000,0xFF000000);
                


  


  However, this creates a corrupted and messed up image. I've also tried using 24bit RGB as well with the same results, and I've also tried using std::copy and std::memcpy instead of using av_image_copy_to_buffer, like this :

  


  for(auto i = 0; i < codecCtx->height; i++)
    std::memcpy(nBuf.data() + i * codecCtx->width, rgbFrame->data[0] + i * rgbFrame->linesize[0], codecCtx->width * 4);


  


  with similarly corrupted results. I've also tried feeding SDL_CreateRGBSurfaceFrom rgbFrame->data[0] directly, and I got the same corrupted image.

  


  I know that rgbFrame is correct, I output it to a raw RGB format and the image was right.

  


  I need to copy this data manually since I cannot have SDL_Renderer and SDL_Textures do this for me since I am using SDL_GPU as my renderer ; the SDL_Surface is just so I can convert the image to a GPU_Image.

  


  If anyone could show me what I am doing wrong or show me an alternate way to get this as a GPU_Image that would be great !