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• Converting ffmpeg CLI command to ffmpeg-python to get bytes of a MPEG Transport Stream data stream ?

  28 août 2023, par kdeckerr

  I have the following code to get the bytes representing the data stream of a .ts video :

  


  def get_datastream_bytes(mpeg_ts_filepath):
    ffmpeg_command = [
        'ffmpeg', '-hide_banner', '-loglevel', 'quiet',
        '-i', mpeg_ts_filepath,
        '-map', '0:d',
        '-c', 'copy',
        '-copy_unknown',
        '-f', 'data',
        'pipe:1'
    ]

    try:
        output_bytes = subprocess.check_output(ffmpeg_command, stderr=subprocess.STDOUT)
        print("Output bytes length:", len(output_bytes))
        return output_bytes
    except subprocess.CalledProcessError as e:
        print("Error:", e.output)


  


  I can then wrap the returned value in io.BytesIO and parse the resulting bytes using another library (klvdata).

  


  This code was fashioned upon a ffmpeg CLI command I adapted from this SO Answer.

  


  ffmpeg -i "C:\inputfile.ts" -map 0:d -c copy -copy_unknown -f:d data pipe:1


  


  ---

  


  What I would really like to do is utilize the Python ffmpeg bindings in ffmpeg-python so that users do not have to install ffmpeg locally. Thus, I have attempted to get a bytes stream from an ffmpeg call like so :

  


  bytestream = (
    ffmpeg.input(input_file)
        .output("pipe:", format="data", codec="copy", copy_unknown=True)
        .run(capture_stdout=True)
)


  


  Though, this and many other, attempts at utilizing ffmpeg-python generally end with the same error :

  


  


  Output #0, data, to 'True' :
[out#0/data @ 00000...] Output file does not contain any stream
Error opening output file True.
Error opening output files : Invalid argument
Traceback (most recent call last) :
...
raise Error('ffmpeg', out, err)
ffmpeg._run.Error : ffmpeg error (see stderr output for detail)

  


  


  ---

  


  How do I convert the ffmpeg CLI command

  


  ffmpeg -i "C:\inputfile.ts" -map 0:d -c copy -copy_unknown -f:d data pipe:1


  


  To an ffmpeg-python call ?

  


• FFMPEG - local video to UDP streaming to OpenCV - video quality degraded

  6 juin 2021, par user3925023

  my goal is to re-stream local video content / desktop screencasting, to an UDP flow that I need to process on a Python script.

  



  Here is the FFMPEG script that I'm using :

  



  ffmpeg -re -i C:\Users\test\Downloads\out.ts -strict -2 -c:v copy -an -preset slower -tune stillimage -b 11200k -f rawvideo udp://127.0.0.1:5000


  



  And here is the simple Python script supposed to read the stream flow :

  



  import cv2

cap = cv2.VideoCapture('udp://127.0.0.1:5000',cv2.CAP_FFMPEG)
if not cap.isOpened():
    print('VideoCapture not opened')
    exit(-1)
width = cap.get(cv2.CAP_PROP_FRAME_WIDTH)  # float
height = cap.get(cv2.CAP_PROP_FRAME_HEIGHT)  # float
print(str(width))
print(str(height))
while True:
    ret, frame = cap.read()
    imgray = frame[int(round((height/100)*70,0)):int(round((width/100)*42,0)), int(round((height/100)*74,0)):int(round((width/100)*54,0))]
    if not ret:
        print('frame empty')
        break
    cv2.imshow('image', imgray)
    if cv2.waitKey(1)&0XFF == ord('q'):
        break
cap.release()


  



  I'm able to visualize portion of the stream video as expect, but I'm facing lot of issue in video quality degradation, specially video artifact probably due missing packet processing :

  



  

  



  Also these are error log I'm geting from script :

  



  [h264 @ 0000026eb272f280] error while decoding MB 105 66, bytestream -21
[h264 @ 0000026eb2fcb740] error while decoding MB 100 53, bytestream -11
[h264 @ 0000026eb272f280] error while decoding MB 32 22, bytestream -11
[h264 @ 0000026ead9ee300] error while decoding MB 60 20, bytestream -25
[h264 @ 0000026eb27f00c0] error while decoding MB 9 62, bytestream -5
[h264 @ 0000026ead9ee780] error while decoding MB 85 44, bytestream -5
[h264 @ 0000026eb27f0800] error while decoding MB 64 25, bytestream -15
[h264 @ 0000026eb272f280] error while decoding MB 112 23, bytestream -17
[h264 @ 0000026eb2735200] error while decoding MB 30 21, bytestream -7


  



  Actually I don't care about video fluidity,I can also reduce the FPS, important thing is the video quality. Not sure if I'm doing wrong on the scripting python part or if I'm using wrong FFMPEG command.

  



  Many Thanks

  


• swresample : Add AVFrame based API

  11 août 2014, par Michael Niedermayer

  swresample : Add AVFrame based API
  Based on commit fb1ddcdc8f51b9d261ae8e9c26b91e81f7b6bf45 by Luca Barbato <lu_zero@gentoo.org>
  
  Adapted for libswresample by Michael Niedermayer
  
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] doc/APIchanges
  • [DH] libswresample/Makefile
  • [DH] libswresample/swresample.h
  • [DH] libswresample/swresample_frame.c
  • [DH] libswresample/version.h