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• Python asyncio subprocess code returns "pipe closed by peer or os.write(pipe, data) raised exception."

  4 novembre 2022, par Duke Dougal

  I am trying to convert a synchronous Python process to asyncio. Any ideas what I am doing wrong ?

  


  This is the synchronous code which successfully starts ffmpeg and converts a directory of webp files into a video.

  


  import subprocess
import shlex
from os import listdir
from os.path import isfile, join

output_filename = 'output.mp4'
process = subprocess.Popen(shlex.split(f'ffmpeg -y -framerate 60 -i pipe: -vcodec libx265 -pix_fmt yuv420p -crf 24 output.mp4'), stdin=subprocess.PIPE)

thepath = '/home/ubuntu/webpfiles/'
thefiles = [f for f in listdir(thepath) if isfile(join(thepath, f))]
for filename in thefiles:
    absolute_path = f'{thepath}{filename}'
    with open(absolute_path, 'rb') as f:
        process.stdin.write(f.read())

process.stdin.close()
process.wait()
process.terminate()


  


  This async code fails :

  


  from os import listdir
from os.path import isfile, join
import shlex
import asyncio

outputfilename = 'output.mp4'

async def write_stdin(proc):
    thepath = '/home/ubuntu/webpfiles/'
    thefiles = [f for f in listdir(thepath) if isfile(join(thepath, f))]
    thefiles.sort()
    for filename in thefiles:
        absolute_path = f'{thepath}{filename}'
        with open(absolute_path, 'rb') as f:
            await proc.communicate(input=f.read())

async def create_ffmpeg_subprocess():
    bin = f'/home/ubuntu/bin/ffmpeg'
    params = f'-y -framerate 60 -i pipe: -vcodec libx265 -pix_fmt yuv420p -crf 24 {outputfilename}'
    proc = await asyncio.create_subprocess_exec(
        bin,
        *shlex.split(params),
        stdin=asyncio.subprocess.PIPE,
        stdout=asyncio.subprocess.PIPE,
        stderr=asyncio.subprocess.PIPE,
    )
    return proc

async def start():
    loop = asyncio.get_event_loop()
    proc = await create_ffmpeg_subprocess()
    task_stdout = loop.create_task(write_stdin(proc))
    await asyncio.gather(task_stdout)

if __name__ == '__main__':
    asyncio.run(start())


  


  The output for the async code is :

  


  pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.


  


  etc - one line for each webp file

  


• Revision 26b6318de8 : Make get_coef_context() branchless. This should significantly speedup cost_coef

  1er juillet 2013, par Ronald S. Bultje

  Changed Paths :
   Modify /vp9/common/vp9_entropy.c

  
   Modify /vp9/common/vp9_entropy.h

  
   Modify /vp9/decoder/vp9_detokenize.c

  
   Modify /vp9/encoder/vp9_encodemb.c

  
   Modify /vp9/encoder/vp9_rdopt.c

  
   Modify /vp9/encoder/vp9_tokenize.c

  
  
  Make get_coef_context() branchless.

  This should significantly speedup cost_coeffs(). Basically what the
  patch does is to make the neighbour arrays padded by one item to
  prevent an eob check in get_coef_context(), then it populates each
  col/row scan and left/top edge coefficient with two times the same
  neighbour - this prevents a single/double context branch in
  get_coef_context(). Lastly, it populates neighbour arrays in pixel
  order (rather than scan order), so we don't have to dereference the
  scantable to get the correct neighbours.

  Total encoding time of first 50 frames of bus (speed 0) at 1500kbps
  goes from 2min10.1 to 2min5.3, i.e. a 2.6% overall speed increase.

  Change-Id : I42bcd2210fd7bec03767ef0e2945a665b851df56

• ffmpeg - overlay a video with rounded corners

  4 novembre 2019, par asi

  I am successfully using overlaying a scaled (smaller) video on top of a larger one but am struggling to understand how could I give the small video a rounded corners mask.

  Edit

  thanks to @loogan comment I’ve managed to get a working command that created applies a circular mask :

  ffmpeg 
  
      -i main.mp4 
  
      -i vignette.mp4 
  
      -filter_complex 
  
        [1:v]scale=300:-1[scaled];
  
        [scaled]split [scaled0][scaled11]; 
  
        [scaled0]trim=end_frame=1,geq='st(3,pow(X-(W/2),2)+pow(Y-(H/2),2));if(lte(ld(3),780*780),255,0)':3:3,loop=-1:1,setpts=N/FRAME_RATE/TB[mask];
  
      [scaled1][mask]alphamerge[cutout];
  
      [0][cutout]overlay=x=W-w:y=0[v];
  
      -map [v] 
  
      -map [a]  
  
      output.mp4

  but how to get from a circle to a rounded rect still eludes me. cant quite get what are the params that geq expects and the math to generate them.

  assuming that the video that needs masking is 200 * 300 and the corners should have a 5px radius, is there a geq command that can create this mask ? maybe en ellipse ?

  or maybe a better way would be to use a pre-made png as a mask ?

  any insights welcome