[FFmpeg-user] Intel libmfx Crash with Hardware Decoding

[Dennis Mungai]

On Mon, 14 Oct 2024 at 18:57, Shane Warren <shanew at innovsys.com> wrote:

> I have a system with Intel Flex 140 cards and use ffmpeg to transcode
> video on an Ubuntu 22.x system. Through a lot of testing, I have come up
> with a flow that handles multicast h264 input (decoding using vaapi) with
> h264/h265 output using QSV. I wanted to use QSV decoding but if I used QSV
> decoding and QSV encoding, but QSV decoding seems to strip A53 captions
> (which I need).
>
> I found one input stream that eventually crashes the vaapi decoder inside
> of libmfx.
>
> The call stack ends up in some function in libfmx:
>
> Program terminated with signal SIGSEGV, Segmentation fault.
>
> #0  0x00007f14b22d9f88 in ?? () from
> /usr/lib/x86_64-linux-gnu/libmfx-gen.so.1.2.10
>
> Is there a way to get symbols for libmfx so I can get a better bug report,
> or some suggestion on how to debug this.
>
> I have switched this stream to software decoding then QSV encoding, and it
> is stable but obviously uses a bit more cpu.
>
> An extra question is: Will the QSV hardware decoder ever support passing
> through a53 captions?
>
> Thanks,
>
> Shane Warren
>

Full ffmpeg command and uncut console output would help in understanding
what's going on in your setup.