[FFmpeg-devel] [PATCH] lavd/v4l2: produce a 0 byte packet when a dequeued buffer's size is unexpected

[Alexander Strasser]

On 2019-06-25 00:08 +0200, Alexander Strasser wrote:
> On 2019-06-05 22:04 +0200, Alexander Strasser wrote:
> > From: Stephan Hilb <stephan at ecshi.net>
> >
> > Behave like we do for V4L2_BUF_FLAG_ERROR, implemented in commit 28f20d2ff4 .
> >
> > For some devices (probably also related to the V4L driver implementation)
> > it happens that when invoking the ioctl DQBUF, the returned buffer is not
> > of the expected size. Here are two examples for such occurrences:
> >
> >     [video4linux2,v4l2 @ 0x258b440] Dequeued v4l2 buffer contains 609596 bytes, but 614400 were expected. Flags: 0x00000001.
> >     /dev/video1: Invalid data found when processing input
> >
> >     [video4linux2,v4l2 @ 0x225f440] Dequeued v4l2 buffer contains 609508 bytes, but 614400 were expected. Flags: 0x00000001.
> >     /dev/video1: Invalid data found when processing input
> >
> > For the ffmpeg CLI tool this means it will stop capturing and exit.
> >
> > The described behaviour was observed at least with one OmniVision USB
> > web cam and with some stk1160 devices.
> >
> > If you search the web for the error message, you will find quite a few
> > instances of this problem. Some of them experienced on other devices.
> >
> > Probably fixes ticket #4795
> >
> > Signed-off-by: Alexander Strasser <eclipse7 at gmx.net>
> > ---
> >
> > This is exactly Stephan's patch except for the commit message.
> >
> > @Stephan: I hope you are OK with my wording in the new message.
> >
> > I contacted Giorgio off-list and also put him in Bcc for this email.
> >
> > He previously reacted, but he probably doesn't have enough time. So if
> > there are no objections I intent to commit in roughly a week if no
> > more issues are found and no objections are raised.
>
> Will push soon.

Pushed.

Not quite as soon as planned, but hopefully better late than never.

[...]

  Alexander