VideoReader hangs when going out of scope

[DinoMan]

I have just started trying this library for loading videos and it has all the features I am looking for. Unfortunately, when I run a simple script to read some video the script doesn't exit and hangs. Here is the minimal example I run:

import decord
vr = decord.VideoReader('example_vid.mp4', width=128, height=128)
vid = vr.get_batch(range(50, 125))

I have checked and it seems to hang on the del function on the _CAPI_VideoReaderFree(self._handle) call.

[DinoMan]

I compiled from source and the problem went away but it would still be good to get an explanation about why this happened,

[zhreshold]

conflicting c libs might cause the error, since deadlocks are too difficult to track I can only imagine something goes wrong in python call.

[dmenig]

I have the same issue after compiling from source.

[MarStarck]

I met the same problem

[KimbingNg]

Same, here

[MarStarck]

I figured out maybe its caused by the video file info not correct. eg, the fps * duration not match the total frame count. But opencv can handle those files. so I read and rewrite those problematic files using OpenCV.

[alsmeirelles]

In my current experiments, it seems that SeekAccurate in C++ API hangs somewhere. I'm using a workaround with asyncio, similar to this: https://stackoverflow.com/questions/34452590/timeout-handling-while-using-run-in-executor-and-asyncio.

I set a timeout of 1 s for the seek_accurate python method and than read the next frame:

        loop = asyncio.get_event_loop()
        for x in range(nframes):
            future = loop.run_in_executor(None, dc_vid.seek_accurate, idx[x])
            try:
                await asyncio.wait_for(future, timeout=1)
            except asyncio.TimeoutError:
                print(f"Timeout for frame {idx[x]}")
                continue
            fr = dc_vid.next().asnumpy()

As a result, you may not get all the frames you wanted and it's slower than native get_batch