From: Brad Smith <brad@comstyle.com>
Subject: Re: ffmpeg on riscv64
To: "Peter J. Philipp" <pjp@delphinusdns.org>, ports@openbsd.org
Date: Tue, 23 Jul 2024 02:42:36 -0400

On 2024-07-23 2:26 a.m., Peter J. Philipp wrote:
> Hi,
>
> I had a long debug on ffmpeg on riscv64 and noticed that it only works with this
> patch:
>
> 0813/stern$ more patch-libavdevice_v4l2_c
> --- libavdevice/v4l2.c.orig.port        Wed Apr 12 20:01:50 2023
> +++ libavdevice/v4l2.c  Mon Jul 22 16:21:58 2024
> @@ -95,11 +95,7 @@
>       int (*open_f)(const char *file, int oflag, ...);
>       int (*close_f)(int fd);
>       int (*dup_f)(int fd);
> -#ifdef __GLIBC__
>       int (*ioctl_f)(int fd, unsigned long int request, ...);
> -#else
> -    int (*ioctl_f)(int fd, int request, ...);
> -#endif
>       ssize_t (*read_f)(int fd, void *buffer, size_t n);
>       void *(*mmap_f)(void *start, size_t length, int prot, int flags, int fd, int64_t offset);
>       int (*munmap_f)(void *_start, size_t length);
>
>
> As you may have just seen that I took out the __GLIBC__ ifdef which may need to
> be defined somewhere, this is best debated by you (the openbsd ports team).
> I just want to make this work with this (partial) script:
>
>              ffmpeg -y  -loglevel verbose -thread_queue_size 256 -copyts \
>                          -vcodec rawvideo \
>                          -f video4linux2 \
>                          -i /dev/video0 \
>                          -c:v copy \
>                          -c:v libvpx-vp9 \
>                          -vcodec libvpx-vp9 \
>                          $OUTFILE  &
>
>                  ffmpeg -y -loglevel quiet -thread_queue_size 256 -copyts \
>                          -acodec pcm_s16le \
>                          -f sndio -i snd/1 \
>                          -c:a libvorbis \
>                          -b:a 128k \
>                          $OUTSOUND
> ---
>
> Unfortunately after fixing the ffmpeg, I noticed that my riscv box is too
> slow so I'll have to look what I can do to speed it up (like offload routines).
>
> Basically in the patch when the ioctl is taking an int instead of a u_long,
> the kernel exited with ENOTTY which I had modified with a DPRINTF that looked
> like so:
>
> Jul 22 20:40:56 stern /bsd: huh? 18446744072641074714 is the case they gave me
>
>      386         default:
>      387                 DPRINTF(1, "huh? %lu is the case they gave me\n", cmd);
>      388                 error = (ENOTTY);
>      389         }
>      390
>      391         return (error);
>
> which is from the /sys/dev/video.c file.
>
> The fix is in userland thus ffmpeg, but it took a little debugging kernel to
> understand what was happening here.
>
> This fix/workaround shouldn't affect anything because of the SYNOPSIS in the
> ioctl(2) manpage:
>
> ---
> SYNOPSIS
>       #include <sys/ioctl.h>
>
>       int
>       ioctl(int d, unsigned long request, ...);
> ---
>
> Fix at your judgement whether this is the way to go.  I'm not on the ports@
> mailing list so if you need feedback at anything CC me directly.
>
> -pjp

https://marc.info/?l=openbsd-ports&m=171831170818836&w=2