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• How can I use both vaapi acceleration and video overlays with ffmpeg

  10 novembre 2019, par nrdxp

  I am fairly new to ffmpeg and I am trying to capture both my webcam and my screen, all using vaapi acceleration (without it, its too slow). I want to overlay the webcam in the bottom right corner using ffmpeg. I need to use kmsgrab, so I can record a Wayland session on Linux.

  What I am doing to work around this is simply open the webcam in a window using the sdl backend, and then call another instance off ffmpeg to record the screen. This isn’t ideal however, since the window with the webcam gets covered up by other windows on fullscreen or when workspace switching. I would much rather encode the webcam on top of the screencast so it is always visible, no matter what I am doing.

  Here is the workaround script I am using right now :

  #!/usr/bin/env zsh
  
  
  
  # record webcam and open it in sdl window
  
  ffmpeg -v quiet -hide_banner -re -video_size 640X480 -hwaccel vaapi -vaapi_device /dev/dri/renderD128 -i /dev/video0 -vf 'format=nv12,hwupload' -c:v hevc_vaapi -f hevc -threads $(nproc) - | ffmpeg -v quiet -i - -f sdl2 - &
  
  
  
  # wait for webcam window to open
  
  until swaymsg -t get_tree | grep 'pipe:' &>/dev/null; do
  
    sleep 0.5
  
  done
  
  
  
  # position webcam in the bottom right corner of screen using sway
  
  swaymsg floating enable
  
  swaymsg resize set width 320 height 240
  
  swaymsg move position 1580 795
  
  swaymsg focus tiling
  
  
  
  #screencast
  
  ffmpeg -format bgra -framerate 60 -f kmsgrab -thread_queue_size 1024 -i - \
  
    -f alsa -ac 2 -thread_queue_size 1024 -i hw:0 \
  
    -vf 'hwmap=derive_device=vaapi,scale_vaapi=w=1920:h=1080:format=nv12' \
  
    -c:v h264_vaapi -g 120 -b:v 3M -maxrate 3M -pix_fmt vaapi_vld -c:a aac -ab 96k -threads $(nproc) \
  
    output.mkv
  
  
  
  kill %1

  So far, I’ve tried adding the webcam as a second input to the screencast and using :

  -filter_complex '[1] scale=w=320:h=240,hwupload,format=nv12 [tmp]; \
  
  [0][tmp] overlay=x=1580:y=795,hwmap=derive_device=vaapi,scale_vaapi=w=1920:h=1080:format=nv12' \

  But I get the error :

  Impossible to convert between the formats supported by the filter 'Parsed_hwupload_1' and the filter 'auto_scaler_0'
  
  Error reinitializing filters!
  
  Failed to inject frame into filter network: Function not implemented

• FFMPEG - Not finding codec parameters

  9 septembre 2024, par Tanner Smith

  I'm trying to convert a sequence of images into a mpeg movie via FFMPEG, although I keep getting an error saying that it could not find the code parameters (Video : mjpeg). A Google search did not bring much up that was useful.

  



  
ffmpeg -f image2 -i /tmp/img%03d.jpg video.mpgFFmpeg version SVN-r0.5.1-4:0.5.1-1ubuntu1, Copyright (c) 2000-2009 Fabrice Bellard, et al.
  configuration : —extra-version=4:0.5.1-1ubuntu1 —prefix=/usr —enable-avfilter —enable-avfilter-lavf —enable-vdpau —enable-bzlib —enable-libgsm —enable-libschroedinger —enable-libspeex —enable-libtheora —enable-libvorbis —enable-pthreads —enable-zlib —disable-stripping —disable-vhook —enable-runtime-cpudetect —enable-gpl —enable-postproc —enable-swscale —enable-x11grab —enable-libdc1394 —enable-shared —disable-static
  libavutil     49.15. 0 / 49.15. 0
  libavcodec    52.20. 1 / 52.20. 1
  libavformat   52.31. 0 / 52.31. 0
  libavdevice   52. 1. 0 / 52. 1. 0
  libavfilter    0. 4. 0 /  0. 4. 0
  libswscale     0. 7. 1 /  0. 7. 1
  libpostproc   51. 2. 0 / 51. 2. 0
  built on Mar  4 2010 12:35:30, gcc : 4.4.3
[mjpeg @ 0x9069870]dqt : 16bit precision
[mjpeg @ 0x9069870]mjpeg : unsupported coding type (c9)
[mjpeg @ 0x9069870]mjpeg : unsupported coding type (cf)
[mjpeg @ 0x9069870]only 8 bits/component accepted
[mjpeg @ 0x9069870]dqt : 16bit precision
[mjpeg @ 0x9069870]huffman table decode error
[mjpeg @ 0x9069870]mjpeg : unsupported coding type (ca)
[mjpeg @ 0x9069870]mjpeg : unsupported coding type (ce)
[mjpeg @ 0x9069870]mjpeg : unsupported coding type (cb)
[mjpeg @ 0x9069870]decode_sos : invalid len (60581)
[mjpeg @ 0x9069870]only 8 bits/component accepted
[mjpeg @ 0x9069870]decode_sos : invalid len (56833)
[mjpeg @ 0x9069870]invalid id 207
[mjpeg @ 0x9069870]mjpeg : unsupported coding type (cd)
[mjpeg @ 0x9069870]huffman table decode error
[image2 @ 0x90682c0]Could not find codec parameters (Video : mjpeg)
/tmp/img%03d.jpg : could not find codec parameters


  



  The images reside in the /tmp directory with names such as img001.jpg and img002.jpg.

  



  Any ideas ?

  



  Thanks
-Tanner

  


• avcodec/lcldec : Check mthread_inlen instead of cliping

  27 juillet 2019, par Michael Niedermayer

  avcodec/lcldec : Check mthread_inlen instead of cliping
  Clipping was added in 2009 to avoid crashes.
  
  The clipped case would produce a 2nd slice with 0 input
  
  thus also producing 0 output.
  
  Subsequent checks will cause decoder failure unless both
  
  slices have the same output length. thus the only way this
  
  would not already fail is if the output from both slices
  
  was 0 bytes.
  Fixes : Timeout (134sec -> 241ms)
  
  Fixes : 15599/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MSZH_fuzzer-5658127116009472
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/lcldec.c