Segfault during finishing/cleanup when using fieldmatch pipeline

[Charles Huber]

I'm trying to apply a moderately complex fieldmatch-based deinterlacing/detelecine-ing filter pipeline before compressing the result using x265.

The filter pipeline was recommended by the docs for the fieldmatch filter.

Unfortuantely once the encode ran "long enough" (10 minutes of input video, 8 or less was insuffcient) ffmpeg would segfault during finishing/cleanup inside ff_scale_eval_dimensions() in libavfilter/scale.c.

This is command I've been using to repro the crash:

ffmpeg \
-i input.mkv \
-filter:v "dejudder,fps=30000/1001,fieldmatch,decimate" \
-c:v huffyuv \
-an \
-f null -

The segfault occurs with release/4.2 as well as 648f5c9382 (master as of a day or two ago)

[Carl Eugen Hoyos]

Please provide the input sample.

[Charles Huber]

Replying to cehoyos:

Please provide the input sample.

Sure! Just finished uploading the sample to streams.videolan.org, should be named ds9-s01e05-repro-02.mkv.

...assuming it maintained the file-name. Otherwise:

size: 430799371 bytes (~410 MiB)
sha256: 593c38c31d24ed362e632dddec7d5ff820ae2f7c794e634b91ea5bc884e7b40e

[Carl Eugen Hoyos]

Regression since a5b2d85f18b38e6fe8e4d99ed4f695ee2dc40db8, also reproducible with -ss 9:00.

[Carl Eugen Hoyos]

Fixed by Paul in da9890f6c7d22eb8ca50aad14a26e71bc69f1855, thank you for the report!

[Charles Huber]

Replying to cehoyos:

Fixed by Paul in da9890f6c7d22eb8ca50aad14a26e71bc69f1855, thank you for the report!

Fix is working great, thank you!