[FFmpeg-devel] [PATCH 1/6] avcodec/packet: add a decoded frame cropping side data type

[James Almer]

On 5/29/2024 10:02 PM, Lynne via ffmpeg-devel wrote:
> On 29/05/2024 23:46, James Almer wrote:
>> Signed-off-by: James Almer <jamrial at gmail.com>
>> ---
>>   libavcodec/packet.h | 14 ++++++++++++++
>>   1 file changed, 14 insertions(+)
>>
>> diff --git a/libavcodec/packet.h b/libavcodec/packet.h
>> index a9a41576da..9dee035690 100644
>> --- a/libavcodec/packet.h
>> +++ b/libavcodec/packet.h
>> @@ -330,6 +330,20 @@ enum AVPacketSideDataType {
>>       */
>>       AV_PKT_DATA_AMBIENT_VIEWING_ENVIRONMENT,
>> +    /**
>> +     * The number of pixels to discard from the
>> +     * top/bottom/left/right border of the decoded frame to obtain 
>> the sub-rectangle
>> +     * intended for presentation.
>> +     *
>> +     * @code
>> +     * u32le crop_top
>> +     * u32le crop_bottom
>> +     * u32le crop_left
>> +     * u32le crop_right
>> +     * @endcode
>> +     */
>> +    AV_PKT_DATA_FRAME_CROPPING,
>> +
>>       /**
>>        * The number of side data types.
>>        * This is not part of the public API/ABI in the sense that it may
> 
> Shouldn't this be propagated to the frame's crop fields, and back from 
> the crop fields to the packet side-data?

We no longer use frames and packets to communicate global side data, and 
we can't use frame cropping values as global metadata for the 
container's header because there's codec level cropping too (like h264 
to remove padding coded at certain dimensions) in them.