(Added Ben to the CC list so he can look at this from the solo6x10 perspective).
On Wednesday, March 23, 2011 12:09:33 Kamil Debski wrote: > Add fourcc definitions for the following compressed formats: > H264, H264 without start codes, MPEG1/2/4 ES, DIVX versions > 3.11, 4, 5.0-5.0.2, 5.03 and up, XVID, VC1 Simple/Main Profile > and VC1 Advanced profile. > --- > Hi, > > During the v4l2 brain storming meeting in Warsaw one of the topics was assigning > fourcc values for compressed elementary streams. All these fourcc values are for compressed elementary *video* streams, right? Because you can also have elementary audio streams (the conexant MPEG encoders can deliver that, although that isn't implemented in the ivtv/cx18 drivers). > > I did some research - which included checking the VC1 and DivX formats. For > other codecs: Xvid, MPEG1/2/4 and H263 the choice of fourcc values was clear. > We have also had discussion regarding the H264 codec, which resulted in having > two fourccs - one with start codes and one without. > > *** MPEG *** > 'MPEG' fourcc will remain reserved for transport/program streams. For elementary > MPEG streams the proposed fourccs are: > * 'MPG1' for MPEG1 > * 'MPG2' for MPEG2 > * 'MPG4' for MPEG4 > > *** H263 *** > For H263 the ‘H263’ fourcc value is reasonable. > > *** Xvid *** > ‘XVID’ fourcc seems a good choice. > > *** H264 *** > H264 elementary stream can come in two flavours: one with start codes and one > without. Following fourccs are proposed: > * 'H264' for NALUs with start codes (start codes are a fixed pattern used to > locate packet boundaries). [1] > * 'AVC1' for NALUs without start codes (framing needs to be provided out of > band, for instance by providing a length field for each packet). [1] > > Links: > [1] http://msdn.microsoft.com/en-us/library/dd757808%28v=vs.85%29.aspx > > *** VC1 *** > VC1 streams have different content based on the profile. VC1 Advanced profile > has start codes and Main and Simple profile relies on the Transport Layer to > provide frame start and length. For VC1 AP the stream content is defined > Annex E. For VC1 SP and MP the streamz by Annex J and Annex L of the SMPTE 421M. > > "In the advanced profile, pictures and slices shall be byte-aligned and carried > in a bitstream data unit (as described in Annex E). Each new picture or a slice, > is detected via start-codes as defined in Annex E. In the simple and main > profiles,pictures shall be byte-aligned. For each coded picture, the pointer to > the coded bitstream, and its size shall be communicated to the decoder by the > Transport Layer. In simple and main profiles, a picture whose coded size is less > than or equal to one byte shall be considered to be a skipped picture." > SMPTE 421M Draft [2] > > Following fourccs are proposed: > * 'WVC1' for VC1 Advanced Profile [1] > * 'WMV3' for VC1 Main and Simple profiles [1] > > Links: > [1] http://wiki.multimedia.cx/index.php?title=VC1 - Fourccs used by Microsoft > [2] http://multimedia.cx/mirror/s421m.pdf - Proposed SMPTE Standard > > *** DivX *** > It is reasonable that versions 3.11, 4 and 5 should have different fourccs. > According to the document I have, there also were important changes and bugfixes > done in DivX 5.0.3. Hence I propose to have a separate fourcc for DivX versions > 5.0.0-5.0.2. > > Following fourccs are proposed: > * 'DIV3' for DivX 3.11 > * 'DIV4' for DivX 4.x > * 'DX50' for Divx 5.0.0-5.0.2 > * 'DIV5' for Divx 5.0.3 and newer > > There are quite a few differences between versions 5.0 - 5.02 and 5.0.3. Those > include: > - quarter pixel motion compensation follows the algorithm described in the > Corrigendum 2 of the ISO/IEC 14496-2 document. (versions prior to 5.0.3 had > used the algorithm described in a previous document) > - new deringing algorithm > - motion vectors are stored in a different way > > I appreciate your comments. Looks good. I think the spec also needs to be updated with the new fourcc's (of course), but also the distinction between multiplexed and elementary streams should be clarified. A note should be added to the STREAM_TYPE and AUDIO_ENCODING/VIDEO_ENCODING controls that those are specific to multiplexed streams only. Regards, Hans > > Best regards, > -- > Kamil Debski > Linux Platform Group > Samsung Poland R&D Center > --- > include/linux/videodev2.h | 13 +++++++++++++ > 1 files changed, 13 insertions(+), 0 deletions(-) > > diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h > index aa6c393..5d80e95 100644 > --- a/include/linux/videodev2.h > +++ b/include/linux/videodev2.h > @@ -372,6 +372,19 @@ struct v4l2_pix_format { > #define V4L2_PIX_FMT_JPEG v4l2_fourcc('J', 'P', 'E', 'G') /* JFIF JPEG > */ > #define V4L2_PIX_FMT_DV v4l2_fourcc('d', 'v', 's', 'd') /* 1394 > */ > #define V4L2_PIX_FMT_MPEG v4l2_fourcc('M', 'P', 'E', 'G') /* MPEG-1/2/4 > */ > +#define V4L2_PIX_FMT_H264 v4l2_fourcc('H', '2', '6', '4') /* H264 with start codes */ > +#define V4L2_PIX_FMT_H264_NO_SC v4l2_fourcc('A', 'V', 'C', '1') /* H264 without start codes */ > +#define V4L2_PIX_FMT_H263 v4l2_fourcc('H', '2', '6', '3') /* H263 > */ > +#define V4L2_PIX_FMT_MPEG1 v4l2_fourcc('M', 'P', 'G', '1') /* MPEG-1 ES > */ > +#define V4L2_PIX_FMT_MPEG2 v4l2_fourcc('M', 'P', 'G', '2') /* MPEG-2 ES > */ > +#define V4L2_PIX_FMT_MPEG4 v4l2_fourcc('M', 'P', 'G', '4') /* MPEG-4 ES > */ > +#define V4L2_PIX_FMT_DIVX3 v4l2_fourcc('D', 'I', 'V', '3') /* DivX 3.11 > */ > +#define V4L2_PIX_FMT_DIVX4 v4l2_fourcc('D', 'I', 'V', '4') /* DivX 4.12 > */ > +#define V4L2_PIX_FMT_DIVX500 v4l2_fourcc('D', 'X', '5', '0') /* DivX 5.00 - 5.02 */ > +#define V4L2_PIX_FMT_DIVX5 v4l2_fourcc('D', 'I', 'V', '5') /* DivX 5.03 - x */ > +#define V4L2_PIX_FMT_XVID v4l2_fourcc('X', 'V', 'I', 'D') /* Xvid > */ > +#define V4L2_PIX_FMT_VC1 v4l2_fourcc('W', 'M', 'V', '3') /* VC-1 Main and simple profiles */ > +#define V4L2_PIX_FMT_VC1_AP v4l2_fourcc('W', 'V', 'C', '1') /* VC-1 Advanced profile */ > > /* Vendor-specific formats */ > #define V4L2_PIX_FMT_CPIA1 v4l2_fourcc('C', 'P', 'I', 'A') /* cpia1 YUV */ > -- > 1.6.3.3 > -- > To unsubscribe from this list: send the line "unsubscribe linux-media" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
