[FFmpeg-devel] [PATCH] avcodec/vvcdec: set pict_type and AV_FRAME_FLAG_KEY

[Rubén Gonzalez]

Hi Nuo Mi,

thanks for your feedback. Unfortunately I don't have enough knowledge/time
to improve the patch. I only mimicked H.26[45].

IMHO, reporting AV_FRAME_FLAG_KEY is better than nothing, so I will send a
new patch only with AV_FRAME_FLAG_KEY logic and create a bug report in trac
to support pict_type.

-    if (!IS_IDR(s))
+    if (IS_IDR(s))
+        fc->frame->flags |= AV_FRAME_FLAG_KEY;
+    else
         ff_vvc_bump_frame(s, fc);

On Sat, Jan 4, 2025 at 2:35 PM Nuo Mi <nuomi2021 at gmail.com> wrote:

> Hi Ruben,
> Thank you for the patch.
> A B/P frame's first slice may be an I slice, so it can't be used to
> determine the picture type.
> The ph_inter_slice_allowed_flag can quickly identify an I frame, but B/P
> frame still requires checking all slices.
>
> On Fri, Jan 3, 2025 at 12:19 AM Ruben Gonzalez <rgonzalez at fluendo.com>
> wrote:
>
>> Update VVC decoder to show frames info with ffprobe and other tools.
>>
>> Tested with:
>> ```
>> wget
>> https://www.itu.int/wftp3/av-arch/jvet-site/bitstream_exchange/VVC/draft_conformance/draft6/CodingToolsSets_E_Tencent_1.zip
>> unzip CodingToolsSets_E_Tencent_1.zip CodingToolsSets_E_Tencent_1.bit
>> ffprobe -hide_banner CodingToolsSets_E_Tencent_1.bit -select_streams v
>> -show_frames -show_entries frame=pict_type,key_frame -of csv
>> ```
>>
>> From
>> ```
>> frame,0,?
>> frame,0,?
>> frame,0,?
>> frame,0,?
>> frame,0,?
>> frame,0,?
>> frame,0,?
>> frame,0,?
>> frame,0,?
>> ```
>>
>> To:
>> ```
>> frame,1,I
>> frame,0,B
>> frame,0,B
>> frame,0,B
>> frame,0,B
>> frame,0,B
>> frame,0,B
>> frame,0,P
>> frame,0,B
>> ```
>>
>> Signed-off-by: Ruben Gonzalez <rgonzalez at fluendo.com>
>> ---
>>  libavcodec/vvc/dec.c | 13 ++++++++++++-
>>  1 file changed, 12 insertions(+), 1 deletion(-)
>>
>> diff --git a/libavcodec/vvc/dec.c b/libavcodec/vvc/dec.c
>> index 1cb168de7e..71408caf7b 100644
>> --- a/libavcodec/vvc/dec.c
>> +++ b/libavcodec/vvc/dec.c
>> @@ -712,7 +712,18 @@ static int frame_start(VVCContext *s,
>> VVCFrameContext *fc, SliceContext *sc)
>>      if ((ret = ff_vvc_set_new_ref(s, fc, &fc->frame)) < 0)
>>          goto fail;
>>
>> -    if (!IS_IDR(s))
>> +    if (sc->sh.r->sh_slice_type == VVC_SLICE_TYPE_B)
>> +        fc->frame->pict_type = AV_PICTURE_TYPE_B;
>> +
>> +    if (sc->sh.r->sh_slice_type == VVC_SLICE_TYPE_P)
>> +        fc->frame->pict_type = AV_PICTURE_TYPE_P;
>> +
>> +    if (sc->sh.r->sh_slice_type == VVC_SLICE_TYPE_I)
>> +        fc->frame->pict_type = AV_PICTURE_TYPE_I;
>> +
>> +    if (IS_IDR(s))
>> +        fc->frame->flags |= AV_FRAME_FLAG_KEY;
>> +    else
>>          ff_vvc_bump_frame(s, fc);
>>
>>      av_frame_unref(fc->output_frame);
>> --
>> 2.47.1
>>
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>