> From: ffmpeg-devel <ffmpeg-devel-boun...@ffmpeg.org> On Behalf Of > Mark Thompson > Sent: Tuesday, July 28, 2020 05:52 > To: FFmpeg development discussions and patches <ffmpeg- > de...@ffmpeg.org> > Subject: Re: [FFmpeg-devel] [PATCH v2 1/4] lavc/vaapi_encode: add > EQUAL_MULTI_ROWS support for slice structure > > On 19/07/2020 08:00, Linjie Fu wrote: > > On Thu, Jun 18, 2020 at 1:36 PM Linjie Fu <linjie.justin...@gmail.com> > wrote: > >> > >> On Tue, May 12, 2020 at 9:49 PM Linjie Fu <linjie...@intel.com> wrote: > >>> > >>> VA_ENC_SLICE_STRUCTURE_EQUAL_MULTI_ROWS is added to in the > latest > >>> libva (1.8.0) which matches the hardware behaviour: > >>> > >>> /** \brief Driver supports any number of rows per slice but they must > be the same > >>> * for all slices except for the last one, which must be equal or > >>> smaller > >>> * to the previous slices. */ > >>> > >>> And VA_ENC_SLICE_STRUCTURE_EQUAL_ROWS is kind of deprecated > for iHD > >>> since it's somehow introduced in [1] however misleading from what we > >>> actually handle, and one row per slice would not get a good quality. > >>> > >>> Caps query support in driver is WIP, and this would fix the multi slice > >>> encoding for VAEntrypointEncSliceLP. > >>> > >>> > [1]<https://github.com/intel/libva/commit/0e6d5441f19bdc674b4da3169d61 > 4d10fd644778> > >>> > >>> Signed-off-by: Linjie Fu <linjie...@intel.com> > >>> --- > >>> libavcodec/vaapi_encode.c | 3 +++ > >>> 1 file changed, 3 insertions(+) > >>> > >>> diff --git a/libavcodec/vaapi_encode.c b/libavcodec/vaapi_encode.c > >>> index cb05ebd..234618a 100644 > >>> --- a/libavcodec/vaapi_encode.c > >>> +++ b/libavcodec/vaapi_encode.c > >>> @@ -1888,6 +1888,9 @@ static av_cold int > vaapi_encode_init_slice_structure(AVCodecContext *avctx) > >>> req_slices = avctx->slices; > >>> } > >>> if (slice_structure & VA_ENC_SLICE_STRUCTURE_ARBITRARY_ROWS > || > >>> +#if VA_CHECK_VERSION(1, 8, 0) > >>> + slice_structure & > VA_ENC_SLICE_STRUCTURE_EQUAL_MULTI_ROWS || > >>> +#endif > >>> slice_structure & > VA_ENC_SLICE_STRUCTURE_ARBITRARY_MACROBLOCKS) { > >>> ctx->nb_slices = req_slices; > >>> ctx->slice_size = ctx->slice_block_rows / ctx->nb_slices; > >>> -- > >>> 2.7.4 > >> > >> Full support is provided in libva[1] and media-driver[2], and we've > >> observed it works for multi slice encoding for AVC. (300+ cases) > >> > >> Prefer to apply this soon with commit message refined. > >> > > Applied, thx. > Treating EQUAL_MULTI_ROWS in the same way as the arbitrary-size cases is > just wrong. > > Consider 9 rows, 4 slices - we pick 4 slices with sizes { 3, 2, 2, 2 }, which > EQUAL_MULTI_ROWS does not allow. > > It isn't possible to split the frame into 4 slices at all with the > EQUAL_MULTI_ROWS structure - the closest options are 3 slices with sizes { 3, > 3, 3 } or 5 slices with sizes { 2, 2, 2, 2, 1 }. > > You can see the same problem at 1080p with five slices.
Umm.. saw the conflicts with the definition/notation in LIBVA. Actually, I doubt whether Hardware still have such limitation which needs the last slice to be no larger than the previous. In the case of 9 rows, 4 slices, the current implementation of rounding works well. {3, 2, 2, 2} . Had sent a mail to the media-driver/libva scrum team to double confirm this, thx. - Linjie _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".