Hi Hugues, as you know, naming is hard and I had to think about this one a little, see my comment below. Le mercredi 20 novembre 2024 à 12:01 +0100, Hugues Fruchet a écrit : > This patch adds the WebP picture decoding kernel uAPI. > > This design is based on currently available VP8 API implementation and > aims to support the development of WebP stateless video codecs > on Linux. > > Signed-off-by: Hugues Fruchet <hugues.fruchet@xxxxxxxxxxx> > --- > Documentation/userspace-api/media/v4l/biblio.rst | 9 +++++++++ > .../userspace-api/media/v4l/pixfmt-compressed.rst | 15 +++++++++++++++ > drivers/media/v4l2-core/v4l2-ioctl.c | 1 + > include/uapi/linux/videodev2.h | 1 + > 4 files changed, 26 insertions(+) > > diff --git a/Documentation/userspace-api/media/v4l/biblio.rst b/Documentation/userspace-api/media/v4l/biblio.rst > index 35674eeae20d..df3e963fc54f 100644 > --- a/Documentation/userspace-api/media/v4l/biblio.rst > +++ b/Documentation/userspace-api/media/v4l/biblio.rst > @@ -447,3 +447,12 @@ AV1 > :title: AV1 Bitstream & Decoding Process Specification > > :author: Peter de Rivaz, Argon Design Ltd, Jack Haughton, Argon Design Ltd > + > +.. _webp: > + > +WEBP > +==== > + > +:title: WEBP picture Bitstream & Decoding Process Specification > + > +:author: Google (https://developers.google.com/speed/webp) > diff --git a/Documentation/userspace-api/media/v4l/pixfmt-compressed.rst b/Documentation/userspace-api/media/v4l/pixfmt-compressed.rst > index 806ed73ac474..e664e70b0619 100644 > --- a/Documentation/userspace-api/media/v4l/pixfmt-compressed.rst > +++ b/Documentation/userspace-api/media/v4l/pixfmt-compressed.rst > @@ -169,6 +169,21 @@ Compressed Formats > this pixel format. The output buffer must contain the appropriate number > of macroblocks to decode a full corresponding frame to the matching > capture buffer. > + * .. _V4L2-PIX-FMT-WEBP-FRAME: > + > + - ``V4L2_PIX_FMT_WEBP_FRAME`` > + - 'WEBP' > + - WEBP VP8 parsed frame, excluding WEBP RIFF header, keeping only the VP8 > + bistream including the frame header, as extracted from the container. > + This format is adapted for stateless video decoders that implement a > + WEBP pipeline with the :ref:`stateless_decoder`. > + Metadata associated with the frame to decode is required to be passed > + through the ``V4L2_CID_STATELESS_VP8_FRAME`` control. > + See the :ref:`associated Codec Control IDs <v4l2-codec-stateless-vp8>`. > + Exactly one output and one capture buffer must be provided for use with > + this pixel format. The output buffer must contain the appropriate number > + of macroblocks to decode a full corresponding frame to the matching > + capture buffer. So after reading more about it, I think we should avoid the usage of the WEBP name, as WEBP is clearly a RIFF based container format and supports 2 totally different codecs. I think we should instead call this V4L2_PIX_FMT_VP8_INTRA_FRAME. We should still document that these are used by WebP for lossy compression, so that readers can correlate. Some folks will still wonder why a separate format, and the I still hold that it fits better for the case we have one driver, with one video node that can handle both, since you can probe these by simply using VIDIOC_ENUM_FMT, its easily discoverable without introducing a new control, etc. regards, Nicolas > > * .. _V4L2-PIX-FMT-VP9: > > diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c > index 0304daa8471d..e2ff03d0d773 100644 > --- a/drivers/media/v4l2-core/v4l2-ioctl.c > +++ b/drivers/media/v4l2-core/v4l2-ioctl.c > @@ -1501,6 +1501,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt) > case V4L2_PIX_FMT_VC1_ANNEX_L: descr = "VC-1 (SMPTE 412M Annex L)"; break; > case V4L2_PIX_FMT_VP8: descr = "VP8"; break; > case V4L2_PIX_FMT_VP8_FRAME: descr = "VP8 Frame"; break; > + case V4L2_PIX_FMT_WEBP_FRAME: descr = "WEBP VP8 Frame"; break; > case V4L2_PIX_FMT_VP9: descr = "VP9"; break; > case V4L2_PIX_FMT_VP9_FRAME: descr = "VP9 Frame"; break; > case V4L2_PIX_FMT_HEVC: descr = "HEVC"; break; /* aka H.265 */ > diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h > index e7c4dce39007..09fff269e852 100644 > --- a/include/uapi/linux/videodev2.h > +++ b/include/uapi/linux/videodev2.h > @@ -757,6 +757,7 @@ struct v4l2_pix_format { > #define V4L2_PIX_FMT_VC1_ANNEX_L v4l2_fourcc('V', 'C', '1', 'L') /* SMPTE 421M Annex L compliant stream */ > #define V4L2_PIX_FMT_VP8 v4l2_fourcc('V', 'P', '8', '0') /* VP8 */ > #define V4L2_PIX_FMT_VP8_FRAME v4l2_fourcc('V', 'P', '8', 'F') /* VP8 parsed frame */ > +#define V4L2_PIX_FMT_WEBP_FRAME v4l2_fourcc('W', 'B', 'P', 'F') /* WEBP VP8 parsed frame */ > #define V4L2_PIX_FMT_VP9 v4l2_fourcc('V', 'P', '9', '0') /* VP9 */ > #define V4L2_PIX_FMT_VP9_FRAME v4l2_fourcc('V', 'P', '9', 'F') /* VP9 parsed frame */ > #define V4L2_PIX_FMT_HEVC v4l2_fourcc('H', 'E', 'V', 'C') /* HEVC aka H.265 */
