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• Getting an error from pyffmpeg when running as a submodule

  3 décembre 2023, par Devin Gardner

  I'm working on building an API using pyffmpeg and pytube to download YouTube videos and convert them to .wav files, synced up with some LED animations. I'm importing pyffmpeg in a submodule, which is then imported by yet another submodule. I'm getting the following error when I run the script (both from my entire package, and in the Python shell directly, and on two different devices with two different OSes) :

  


  This is the error I get from the shell on my MacBook :

  


  Traceback (most recent call last):&#xA;  File "<stdin>", line 1, in <module>&#xA;  File "/path/to/venv/lib/python3.11/site-packages/pyffmpeg/__init__.py", line 163, in convert&#xA;    raise Exception(self.error)&#xA;Exception&#xA;</module></stdin>

  


  And this is the error I get on my Raspberry Pi when I run the full program :

  


    File "/path/to/venv/lib/python3.11/site-packages/pyffmpeg/__init__.py", line 154, in convert
    if 'Output #0' not in stderr:
                          ^^^^^^
UnboundLocalError: cannot access local variable 'stderr' where it is not associated with a value


  


  I've tracked down the relevant code in the __init__.py file of pyffmpeg, but I'm not sure how to fix the problem.

  


          if 'Output #0' not in stderr:
            lines = stderr.splitlines()
            if len(lines) > 0:
                self.error = lines[-1]
            else:
                self.error = ""

            if self.enable_log:
                self.logger.error(self.error)
            raise Exception(self.error)
        else:
            self.error = ''
            if self.enable_log:
                self.logger.info('Conversion Done')
        return out


  


  Anyone have any ideas ?

  


• problem with changing the frames in an video with opencv

  5 septembre 2023, par Avizipi

  I have a code that runs in the last few months without any problem. The code shows an image from a video with extra data from the relevant db. using the keyboard you can jump around some frames and get better insights. However, in the last week changing the frame of the video stopped working.

  


  I built a small script that show the problem.

  


  import cv2

vid_cap_reader_path = "vid_230830_122746_C.avi"
cap_rgb = cv2.VideoCapture(vid_cap_reader_path)

k = 0
while 1:
    if k == ord("q"):
        break
    if k == ord("b"):
        before = cap_rgb.get(cv2.CAP_PROP_POS_FRAMES)
        cap_rgb.set(cv2.CAP_PROP_POS_FRAMES, before + 30.0)
        after = cap_rgb.get(cv2.CAP_PROP_POS_FRAMES)
        print(f"before = {before} after = {after}")
    ret, img = cap_rgb.read()
    if ret:
        cv2.imshow("bla", img)
        k = cv2.waitKey(0)
    else:
        break


  


  This is what is printed to the terminal :

  


  [mpeg4 @ 0x1d87400] warning: first frame is no keyframe
before = 36.0 after = 0.0
before = 67.0 after = 0.0
[mpeg4 @ 0x1d87400] warning: first frame is no keyframe
before = 40.0 after = 0.0
[mpeg4 @ 0x1d87400] warning: first frame is no keyframe


  


  The video itself doesn't "jump" for the next frame as expected and also most of the properties that opencv have return 0. I tested also CAP_PROP_FRAME_COUNT, and CAP_PROP_POS_MSEC without any lack, although the msec flag did give non-zero results which make no sense.

  


  It is also important to mention that I am building this application in a docker file and I am not using a specific version for my requirements. The tests here are with opencv-python==4.7.0.68. Also, the videos are working fine while playing them on VLC.

  


  I was looking around the net for a similar problem from the recent time and didn't find much except this github issue that may be similar. I started to downgrade opencv one by one without any luck.

  


  Maybe someone here can help with this issue, or give me a lead to doing something different.

  


• fftools/ffmpeg : move sending filtergraph commands to a separate function

  16 juillet 2023, par Anton Khirnov

  fftools/ffmpeg : move sending filtergraph commands to a separate function
  Stop accessing filtergraph internals from keyboard reading code.
  

  • [DH] fftools/ffmpeg.c
  • [DH] fftools/ffmpeg.h
  • [DH] fftools/ffmpeg_filter.c