ZeroDivisionError with empty video document

[owencking]

Bug Description

Running SWT detection v8.6, upon encountering a zero byte video, this error occurred:

Traceback (most recent call last):
 File "/app/cli.py", line 88, in <module>
 out_mmif = clamsapp.annotate(in_data, **params)
 File "/usr/local/lib/python3.10/site-packages/clams/app/__init__.py", line 193, in annotate
 annotated, cuda_profiler = self._profile_cuda_memory(self._annotate)(mmif, **refined)
 File "/usr/local/lib/python3.10/site-packages/clams/app/__init__.py", line 582, in wrapper
 result = func(*args, **kwargs)
 File "/app/app.py", line 57, in _annotate
 self._annotate_timepoints(mmif, **parameters)
 File "/app/app.py", line 92, in _annotate_timepoints
 vdh.capture(video)
 File "/usr/local/lib/python3.10/site-packages/mmif/utils/video_document_helper.py", line 620, in capture
 dur = round(fc / fps, 3) * 1000
ZeroDivisionError: float division by zero

Reproduction steps

Touch a filename to create a zero byte mp4 file, create blank/source MMIF, then run SWT detection v8.6.

Expected behavior

Honestly, I don't know what is the desirable behavior here. Should it just create a view without any annotations, or perhaps some error view?

Log output

Screenshots

No response

Additional context

No response

[keighrim]

moving to SDK repo, as it should return an error view with code 500.

[keighrim]

$ touch ~/a.mp4
$ ls -lda ~/a.mp4
-rw-r--r--. 1 krim grad 0 Jul 7 19:18 /home/krim/a.mp4
$ clams source video:/home/krim/a.mp4 | curl -d@- 127.0.0.1:22001
{
 "metadata": {
 "mmif": "http://mmif.clams.ai/1.2.0"
 },
 "documents": [
 {
 "@type": "http://clams.ai/vocabulary/type/VideoDocument/v2",
 "properties": {
 "mime": "video",
 "id": "d1",
 "location": "file:///home/krim/a.mp4"
 }
 }
 ],
 "views": [
 {
 "id": "v_0",
 "metadata": {
 "timestamp": "2026-07-07T23:17:51.343181Z",
 "app": "http://apps.clams.ai/swt-detection/v8.6",
 "error": {
 "message": "<class 'ZeroDivisionError'>: float division by zero",
 "stackTrace": " File \"/usr/local/lib/python3.10/site-packages/clams/restify/__init__.py\", line 200, in post\n self.cla.annotate(raw_data, **raw_params))\n\t\n File \"/usr/local/lib/python3.10/site-packages/clams/app/__init__.py\", line 193, in annotate\n annotated, cuda_profiler = self._profile_cuda_memory(self._annotate)(mmif, **refined)\n\t\n File \"/usr/local/lib/python3.10/site-packages/clams/app/__init__.py\", line 582, in wrapper\n result = func(*args, **kwargs)\n\t\n File \"/app/app.py\", line 57, in _annotate\n self._annotate_timepoints(mmif, **parameters)\n\t\n File \"/app/app.py\", line 92, in _annotate_timepoints\n vdh.capture(video)\n\t\n File \"/usr/local/lib/python3.10/site-packages/mmif/utils/video_document_helper.py\", line 620, in capture\n dur = round(fc / fps, 3) * 1000\n"
 }
 },
 "annotations": []
 }
 ]
}

Interesting... It returns the expected error with 500.

[keighrim]

Aha, cli.py isn't fully mirroring more robust error handling from the flask instance.

$ clams source video:/home/krim/a.mp4 | pdm run -i --rm -v /home:/home ghcr.io/clamsproject/app-swt-detection:v8.6 python cli.py
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x563043dff980] moov atom not found
Traceback (most recent call last):
 File "/app/cli.py", line 86, in <module>
 out_mmif = clamsapp.annotate(in_data, **params)
 File "/usr/local/lib/python3.10/site-packages/clams/app/__init__.py", line 193, in annotate
 annotated, cuda_profiler = self._profile_cuda_memory(self._annotate)(mmif, **refined)
 File "/usr/local/lib/python3.10/site-packages/clams/app/__init__.py", line 582, in wrapper
 result = func(*args, **kwargs)
 File "/app/app.py", line 57, in _annotate
 self._annotate_timepoints(mmif, **parameters)
 File "/app/app.py", line 92, in _annotate_timepoints
 vdh.capture(video)
 File "/usr/local/lib/python3.10/site-packages/mmif/utils/video_document_helper.py", line 620, in capture
 dur = round(fc / fps, 3) * 1000
ZeroDivisionError: float division by zero

Fix is on the way.