On Mon, 2019-08-19 at 14:41 +0200, Paul Kocialkowski wrote: > Hi, > > On Fri 16 Aug 19, 13:01, Ezequiel Garcia wrote: > > The V4L2_PIX_FMT_H264_SLICE_RAW name was originally suggested > > because the pixel format would represent H264 slices without any > > start code. > > > > However, as we will now introduce a start code menu control, > > give the pixel format a more meaningful name, while it's > > still early enough to do so. > > I definitely agree that SLICE_RAW is not the suffix we are looking for, but > I'm > not sure that _SLICE is self-describing given that we can operate either > per-frame or per-slice, and _SLICE sort of implies the latter.
This is not entirely so, per-frame or per-slice mode refer to the granularity of the stateless API, the pixel format is still composed of H264 NALU slices. As per the documentation, the decode_mode and the start_code are modifiers of the pixel format. As long as this is properly speced, the V4L2_PIX_FMT_H264_SLICE looks pretty OK to me. > Also, VP8 uses > _FRAME to clearly indicate that it operates per-frame. > This is because VP8 doesn't have any concept of slices, the encoded unit is a video frame. > In addition, the _SLICE suffix is used by MPEG-2 in the stable API. Since we > certainly want MPEG-2 to allow per-slice and per-frame decoding as well as > H.264 and that the _SLICE format is specified to be the broken "concatenated > slices" that cedrus expects, we probably want to use another suffix. This way, > we could deprecated MPEG2_SLICE and introduce a new format for MPEG-2 that > would > have consistent naming with the other mpeg formats. > > One suggestion I had was to call it H264_PARSED (and apply this to MPEG-2 and > HEVC when similar controls to H.264 are set in place for them). I think Hans > had > another suggestion for the name but I don't recall what it was at this point. > > Either way, if this has to be some debate, we could perhaps take it off your > series and stay with SLICE_RAW for now, as long as we do rename it before > making > the API stable. > > What do you think? > With the new pixel format modifiers (decode_mode and start_code), the _RAW suffix now has no meaning. Now, we could name it _PARSED or _SLICE. As long as this is properly documented (as it is now), that'd be fine. Now, to be completely honest, this discussion sounds like bikeshedding to me. Thanks, Eze
