webm files don't work correctly

[speechwrecko]

Description:
Using scene detect on webm files doesn't work. With OpenCV it only loads about 2/5% of the total frame or 3-ish minutes of video. If you switch to pyav it seems to calculate the correct frames but produces the following exception when saving images

File "keyframe.py", line 94, in find_scenes
scene_images = scenedetect.scene_manager.save_images(scene_list, video, num_images=1, output_dir="temp_img")
File "/home/jason/.local/lib/python3.8/site-packages/scenedetect/scene_manager.py", line 481, in save_images
aspect_ratio = video.aspect_ratio
File "/home/jason/.local/lib/python3.8/site-packages/scenedetect/backends/pyav.py", line 214, in aspect_ratio
self._codec_context.display_aspect_ratio.numerator /
AttributeError: 'NoneType' object has no attribute 'numerator'

Example:

Include code samples that demonstrate the issue:

    video = open_video('file.webm', backend='pyav')
    scene_manager = SceneManager()
    scene_manager.add_detector(ContentDetector(threshold=threshold))
    scene_manager.detect_scenes(video)
    scene_list = scene_manager.get_scene_list()
    scene_images = scenedetect.scene_manager.save_images(scene_list, video, num_images=1, output_dir="temp_img")

Environment:

[PySceneDetect] PySceneDetect 0.6.2

Media/Files:

Appears on any webm file

[Breakthrough]

Good find, do you happen to know if OpenCV gets the aspect ratio correct?

That aside, this is a bug since if we can't determine aspect ratio it should assume 1.0 instead of crashing. Thanks for the report.

[Breakthrough]

Does this happen with all videos? I was able to successfully process some with OpenCV without issue.

[Breakthrough]

Do you have an example you can share that demonstrates the bug? This should be fixed in the next release, but I wasn't able to reproduce the issue so hoping to be able to verify the fix first somehow. Thanks!

[Breakthrough]

Have done my best to avoid crashing issues with this, which will be included in the next version. Unfortunately I'm unable to verify the fix, but if anyone runs into this again, feel free to open a new issue.