[FFmpeg-devel] [PATCH 1/2] hevcdec: Miss the location of chroma samples when exporting stream parameters

[Hendrik Leppkes]

On Wed, May 16, 2018 at 10:49 AM, Xiang, Haihao <haihao.xiang at intel.com> wrote:
> On Wed, 2018-05-16 at 10:17 +0200, Hendrik Leppkes wrote:
>> On Wed, May 16, 2018 at 9:19 AM, Haihao Xiang <haihao.xiang at intel.com> wrote:
>> > Signed-off-by: Haihao Xiang <haihao.xiang at intel.com>
>> > ---
>> >  libavcodec/hevcdec.c | 5 +++++
>> >  1 file changed, 5 insertions(+)
>> >
>> > diff --git a/libavcodec/hevcdec.c b/libavcodec/hevcdec.c
>> > index c8877626d2..13d868bb4f 100644
>> > --- a/libavcodec/hevcdec.c
>> > +++ b/libavcodec/hevcdec.c
>> > @@ -344,6 +344,11 @@ static void export_stream_params(AVCodecContext *avctx,
>> > const HEVCParamSets *ps,
>> >          avctx->colorspace      = AVCOL_SPC_UNSPECIFIED;
>> >      }
>> >
>> > +    if (sps->vui.chroma_loc_info_present_flag)
>> > +        avctx->chroma_sample_location = sps-
>> > >vui.chroma_sample_loc_type_top_field + 1;
>> > +    else
>> > +        avctx->chroma_sample_location = AVCHROMA_LOC_UNSPECIFIED;
>> >
>>
>> This change is incomplete, refer to the patch I proposed earlier:
>> http://ffmpeg.org/pipermail/ffmpeg-devel/2018-April/228100.html
>>
>
> Sorry I didn't see your proposal before. Per spec, once
> chroma_loc_info_present_flag is set, chroma_format_idc should be 1. I think it
> would be better to add some checks when parsing the sequence parameters.
>

It makes no real difference because you still need the check to be
able to set the LEFT default value for  4:2:0 only.

- Hendrik