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• avcodec/mdec : DC reading for STRv1 is like STRv2

  2 janvier 2024, par aybe aybe

  avcodec/mdec : DC reading for STRv1 is like STRv2
  As I understand, support for .STR files is broken for almost 10 years now (since 161442ff2c4b0dd8a5072c6bbe6bf55303fffccf it seems).
  Currently, ffmpeg fails with tons of errors like this on version 1 STRs, e.g. Wipeout 1 :
  
  [mdec @ 00000000027c72c0] ac-tex damaged at 1 9
  What happens is that only the audio is present in the video file.
  Anyway, that one character patch fixes the problem, video is now rendered.
  Signed-off-by : aybe <aybe@users.noreply.github.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/mdec.c

• Issue with yt-dlp and FFMPEG Converting Webm to MP4 for 360 video : Unsupported channel layout "ambisonic 1"

  22 janvier 2024, par William L W L

  I am trying to convert .webm files to mp4. These are 360 videos that have been downloaded using yt-dlp.

  


  I have been using this command successfully, but it does not work on an M2 macbook pro. It works fine on PC.

  


  ffmpeg -y -i "/Users/x/Movies/Tropical_Rainforest_360.webm" -c:v libx265 -preset fast -crf 21 -vf "scale=4096x4096:out_range=full" -pix_fmt yuvj420p -aspect 1:1 -movflags faststart "/Users/x/Movies/Tropical_Rainforest_360.mp4"


  


  The error messages are as follows :

  


  [aac @ 0x12ae1fea0] Unsupported channel layout "ambisonic 1"
[aac @ 0x12ae1fea0] Qavg: nan
[aost#0:1/aac @ 0x12ae1fc30] Error while opening encoder - maybe incorrect parameters such as bit_rate, rate, width or height.
Error while filtering: Invalid argument
[swscaler @ 0x110dd0000] deprecated pixel format used, make sure you did set range correctly
[swscaler @ 0x120158000] deprecated pixel format used, make sure you did set range correctly
[swscaler @ 0x130208000] deprecated pixel format used, make sure you did set range correctly
    Last message repeated 1 times
[out#0/mp4 @ 0x600003f8c480] Nothing was written into output file, because at least one of its streams received no packets.
frame=    0 fps=0.0 q=0.0 Lsize=       0kB time=N/A bitrate=N/A speed=N/A    
Conversion failed!



  


  Context : I work in an educational setting which caters for vulnearble pupils. We cannot use Youtube in real time, this is mainly due to adverts or suggested videos that may trigger our pupils. Some children have mental health issues. Some children have also not been outdoors for several months/years due to medical conditions. We use 360 videos and VR to help bring the outside world inside, The YoutubeVR app is not an option since there is no way to install adblockers.

  


  The same script above works fine on a PC virtual machine which I can remote into from my Mac.

  


• Transcode H264 to AV1

  17 février 2024, par Crear

  We have some roadside cameras deployed and due to the supply chain issue (also the cost) we installed 1080P@H264 encoder.

  


  I know that AV1 is significantly more efficient than H264, but transcoding H264 to AV1 may result in quality loss.

  


  My purpose is to reduce some space while minimizing the quality loss, is there a python or FFmpeg command that can do it ? My major concern is quality loss, but if I use the same bitrate, it won’t reduce the size.

  


  We have years of data so we can’t really look into the videos one by one to determine the optimal bitrate, sometimes when the weather is extreme, the higher dynamic in the frames results in a bigger H264 file size. I don’t want to lose those details because it can help fine-tone the detection models.