[FFmpeg-devel] [PATCH] vulkan_av1: Set force_integer_mv on intra frames

[Mark Thompson]

On 27/04/2024 14:47, Ronald S. Bultje wrote:
> Hi,
> 
> On Sat, Apr 27, 2024 at 9:40 AM Mark Thompson <sw at jkqxz.net> wrote:
> 
>> The flag in CBS is the value read from the bitstream (as required for
>> passthrough), but the specification overrides that by setting it
>> immediately after reading if the frame is intra.
>> ---
>> This is already done for DXVA and VDPAU.  Also wondering whether this
>> should be done for VAAPI?
>>
>>  libavcodec/vulkan_av1.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/libavcodec/vulkan_av1.c b/libavcodec/vulkan_av1.c
>> index 25ab4ecc70..694e643954 100644
>> --- a/libavcodec/vulkan_av1.c
>> +++ b/libavcodec/vulkan_av1.c
>> @@ -435,7 +435,7 @@ static int vk_av1_start_frame(AVCodecContext
>> *avctx,
>>              .render_and_frame_size_different =
>> frame_header->render_and_frame_size_different,
>>              .allow_screen_content_tools =
>> frame_header->allow_screen_content_tools,
>>              .is_filter_switchable = frame_header->is_filter_switchable,
>> -            .force_integer_mv = frame_header->force_integer_mv,
>> +            .force_integer_mv = frame_header->force_integer_mv ||
>> !(frame_header->frame_type & 1),
>>              .frame_size_override_flag =
>> frame_header->frame_size_override_flag,
>>              .buffer_removal_time_present_flag =
>> frame_header->buffer_removal_time_present_flag,
>>              .allow_intrabc = frame_header->allow_intrabc,
>> --
>> 2.43.0
>>
> 
> Wouldn't it be better to adjust the CBS reader then? Prevents us from
> having to re-do this in every hw wrapper.

How would you suggest doing this?

We could add a derived field force_integer_mv somewhere else (av1dec?) but that doesn't seem obviously better for use in the "copy stuff from frame header" function.

- Mark