On Thu, 30. Apr 01:39, Ming Qian wrote:
> > From: Andriy Gelman <andriy.gel...@gmail.com>
> >
> > v4l2_m2m devices may send an empty packet/frame while draining to indicate
> > that all capture buffers have been flushed.
> >
> > Currently, the empty packet/frame is not handled correctly:
> > When encoding, the empty packet is forwarded to the muxer, usually creating
> > warnings.
> > When decoding, a reference to the memory is created anyway.. Since in the
> > past this memory contained a decoded frame, it results in an extra frame
> > being
> > decoded.
> >
> > This commit discards the empty packet/frame.
> >
> > References:
> > linux/Documentation/media/uapi/v4l/dev-decoder.rst:
> >
> > "The last buffer may be empty (with :c:type:`v4l2_buffer` bytesused = 0)
> > and in that case it must be ignored by the client, as it does not
> > contain a decoded frame."
> >
> > linux/Documentation/media/uapi/media/v4l/vidioc-encoder-cmd.rst:
> >
> > "...This buffer may be empty, indicated by the
> > driver setting the ``bytesused`` field to 0."
> >
> > Signed-off-by: Andriy Gelman <andriy.gel...@gmail.com>
> > ---
> > libavcodec/v4l2_context.c | 9 +++++++++
> > 1 file changed, 9 insertions(+)
> >
> > diff --git a/libavcodec/v4l2_context.c b/libavcodec/v4l2_context.c index
> > 6c2db5c849..f0ecc18ebd 100644
> > --- a/libavcodec/v4l2_context.c
> > +++ b/libavcodec/v4l2_context.c
> > @@ -393,6 +393,15 @@ dequeue:
> > return NULL;
> > }
> >
> > + if (ctx_to_m2mctx(ctx)->draining
> > && !V4L2_TYPE_IS_OUTPUT(ctx->type)) {
> > + int bytesused = V4L2_TYPE_IS_MULTIPLANAR(buf.type) ?
> > + buf.m.planes[0].bytesused : buf.bytesused;
> > + if (bytesused == 0) {
> > + ctx->done = 1;
> > + return NULL;
> > + }
> > + }
> > +
> > avbuf = &ctx->buffers[buf.index];
> > avbuf->status = V4L2BUF_AVAILABLE;
> > avbuf->buf = buf;
> > --
> > 2.25.1
> >
>
> Lgtm
>
Thanks.
Will apply both patches on Friday if no one objects.
--
Andriy
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