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• Terminal prompt disappears after asyncio script with ffmpeg writing things is run

  8 avril 2022, par David I

  I've followed a simple example https://docs.python.org/3/library/asyncio-task.html#running-tasks-concurrently in trying to learn the basics of asyncio.

  


  It works as expected with most commands however when employed with three ffmpeg commands that take an input and write an output, see the example below, the terminal window prompt becomes invisible after the script has (seemingly successfully run). It responds to typed commands and shows the result but the input isn't shown until I start a new terminal session. It's the same with Code's bash terminal as with Kitty.

  


  It doesn't seem to be a "write to file system concurrantly" problem as the echo lines don't produce the problem. The ffprobe commands don't produce it either but "command1" and 2 and 3 always do. It's the same with other ffmpeg commands that write to the file system via a conversion or a split of an audio input file.

  


  The processes exit with 0 and ffmpeg issues most output to stderr so the output looks like

  


  


  ['ffmpeg -y -i "01 Dia Artio.m4a" "oof1.wav"' exited with 0]
[stderr]
ffmpeg version N-104926-gc8b5f2848d Copyright (c) 2000-2021 the FFmpeg developers
built with gcc 11 (GCC)...

  


  


  import asyncio

async def run(cmd):
    proc = await asyncio.create_subprocess_shell(
        cmd,
        stdout=asyncio.subprocess.PIPE,
        stderr=asyncio.subprocess.PIPE)

    stdout, stderr = await proc.communicate()
    print(f'[{cmd!r} exited with {proc.returncode}]')
    print(f'[stderr]\n{stderr.decode()}')

async def main():
    # Schedule three calls *concurrently*:
    command1 = "ffmpeg -y -i '01 Dia Artio.m4a' 'oof1.wav'"
    command2 = "ffmpeg -y -i '03 Cleansing.m4a' 'oof3.wav'"
    command3 = "ffmpeg -y -i 'The Cranberries - 10 - Dreaming My Dreams.flac' 'oof2.wav'"

    cat1 = "echo 'cat' > cat.txt"
    cat2 = "echo 'kitteh' > kat.txt"
    cat3 = "echo 'eirlyss' > eirlyss.txt"

    ffprobe1 = "ffprobe oof1.wav"
    ffprobe2 = "ffprobe oof2.wav"
    ffprobe3 = "ffprobe oof1.wav"
    await asyncio.gather(
        run(command1),
        run(command2),
        run(command3)
    )
    
 
asyncio.run(main())


  


  This problem has only happened with this combination of asyncio and ffmpeg and it appears consistent and I would very much like to know what might be the cause of it.

  


  I'm on Fedora 35 with Python 3.10.4 and a self built (via ffmpegs instructs) ffmpeg from a few months back).

  


• avcodec/aom_film_grain : implement AFGS1 parsing

  26 février 2024, par Niklas Haas

  avcodec/aom_film_grain : implement AFGS1 parsing
  Based on the AOMedia Film Grain Synthesis 1 (AFGS1) spec :
  
    https://aomediacodec.github.io/afgs1-spec/
  The parsing has been changed substantially relative to the AV1 film
  
  grain OBU. In particular :
  1. There is the possibility of maintaining multiple independent film
  
     grain parameter sets, and decoders/players are recommended to pick
  
     the one most appropriate for the intended display resolution. This
  
     could also be used to e.g. switch between different grain profiles
  
     without having to re-signal the appropriate coefficients.
  2. Supporting this, it's possible to *predict* the grain coefficients
  
     from previously signalled parameter sets, transmitting only the
  
     residual.
  3. When not predicting, the parameter sets are now stored as a series of
  
     increments, rather than being directly transmitted.
  4. There are several new AFGS1-exclusive fields.
  I placed this parser in its own file, rather than h2645_sei.c, since
  
  nothing in the generic AFGS1 film grain payload is specific to T.35, and
  
  to compartmentalize the code base.
  

  • [DH] libavcodec/aom_film_grain.c
  • [DH] libavcodec/aom_film_grain.h

• FFmpeg - EXRs to MOV, repeating first 24 frames

  16 mai 2015, par JGazlyVFX

  I’m trying to convert EXRs to h264:MOV, in their native resolution. It will create the QT, but when I play back it back, it is looping the first 24 frames, over and over for what seems to be the duration of the frame sequence.

  Below is the command I’m running, Along with Output :

  /usr/bin/ffmpeg_build2/ffmpeg -start_number 001001 -r 24 -i /Volumes/storage/ff/plates/BC/BC0535/BC0535_ref2_20150408/2880x2160/EXR/BC0535_ref2.%06d.exr -vcodec libx264 -pix_fmt yuv420p -r 24 /Volumes/vfx_sftp/ff/ff_prod/TO_PROD/Fan4_BC_QT_PT2_20150515/BC0535_ref2_fr_20.mov