On Fri 30 August 2013 09:28:36 Pawel Osciak wrote: > On Fri, Aug 30, 2013 at 3:42 PM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote: > > > On 08/30/2013 04:17 AM, Pawel Osciak wrote: > > > Add bits for previous, golden and altref frame types. > > > > > > Signed-off-by: Pawel Osciak <posciak@xxxxxxxxxxxx> > > > > Kamil, is this something that applies as well to your MFC driver? > > > > > --- > > > include/uapi/linux/videodev2.h | 4 ++++ > > > 1 file changed, 4 insertions(+) > > > > > > diff --git a/include/uapi/linux/videodev2.h > > b/include/uapi/linux/videodev2.h > > > index 437f1b0..c011ee0 100644 > > > --- a/include/uapi/linux/videodev2.h > > > +++ b/include/uapi/linux/videodev2.h > > > @@ -687,6 +687,10 @@ struct v4l2_buffer { > > > #define V4L2_BUF_FLAG_TIMESTAMP_UNKNOWN 0x0000 > > > #define V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC 0x2000 > > > #define V4L2_BUF_FLAG_TIMESTAMP_COPY 0x4000 > > > +/* VP8 special frames */ > > > +#define V4L2_BUF_FLAG_PREV_FRAME 0x10000 /* VP8 prev frame > > */ > > > +#define V4L2_BUF_FLAG_GOLDEN_FRAME 0x20000 /* VP8 golden > > frame */ > > > +#define V4L2_BUF_FLAG_ALTREF_FRAME 0x40000 /* VP8 altref > > frame */ > > > > Would it be an idea to use the same bit values as for > > KEYFRAME/PFRAME/BFRAME? > > After all, these can never be used at the same time. I'm a bit worried > > that the > > bits in this field are eventually all used up by different encoder flags. > > > > VP8 also has a concept of I and P frames and they are orthogonal to the > concept of Prev, Golden and Alt. There is no relationship at all, i.e. we > can't infer I P from Prev Golden Alt and vice versa. Ah, OK. Me no VP8 expert :-) > For the I, P > dimension, we need one bit, but same could be said about H264, we need 2 > bits, not 3 there (if it's not I or P, it's B), and we have 3 bits > nevertheless. > For Prev Golden Alt dimension, we do need 3 bits. > Now, technically, in VP8, the first bit of the frame header indicates if > the frame is I or P, so we could technically use that in userspace and > overload I P B to mean Prev Golden Alt for VP8. But while I understand the > problem with running out of bits very well, as I and P exist in VP8 as > well, it would be pretty confusing, so it's a trade-off that should be > carefully weighted. Are prev/golden/altref frames mutually exclusive? If so, then perhaps we should use a two-bit mask instead of three bits. And those two-bits can later be expanded to more to support codecs that have more than four different frame types. Regards, Hans > > Regards, > Pawel > > > > Regards, > > > > Hans > > > > > > > > /** > > > * struct v4l2_exportbuffer - export of video buffer as DMABUF file > > descriptor > > > > > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html