[FFmpeg-devel] [PATCH v2 02/18] cbs_h264: Add support for frame packing arrangement SEI messages

[James Almer]

On 2/21/2021 4:51 PM, Mark Thompson wrote:
> ---
>   libavcodec/cbs_h264.h                 | 23 ++++++++++++++++
>   libavcodec/cbs_h2645.c                |  6 +++++
>   libavcodec/cbs_h264_syntax_template.c | 39 +++++++++++++++++++++++++++
>   3 files changed, 68 insertions(+)
> 
> diff --git a/libavcodec/cbs_h264.h b/libavcodec/cbs_h264.h
> index 9eb97eae24..1466ed12fa 100644
> --- a/libavcodec/cbs_h264.h
> +++ b/libavcodec/cbs_h264.h
> @@ -282,6 +282,29 @@ typedef struct H264RawSEIRecoveryPoint {
>       uint8_t changing_slice_group_idc;
>   } H264RawSEIRecoveryPoint;
>   
> +typedef struct H264RawSEIFramePackingArrangement {
> +    uint32_t frame_packing_arrangement_id;
> +    uint8_t  frame_packing_arrangement_cancel_flag;
> +
> +    uint8_t  frame_packing_arrangement_type;
> +    uint8_t  quincunx_sampling_flag;
> +    uint8_t  content_interpretation_type;
> +    uint8_t  spatial_flipping_flag;
> +    uint8_t  frame0_flipped_flag;
> +    uint8_t  field_views_flag;
> +    uint8_t  current_frame_is_frame0_flag;
> +    uint8_t  frame0_self_contained_flag;
> +    uint8_t  frame1_self_contained_flag;
> +    uint8_t  frame0_grid_position_x;
> +    uint8_t  frame0_grid_position_y;
> +    uint8_t  frame1_grid_position_x;
> +    uint8_t  frame1_grid_position_y;
> +    uint8_t  frame_packing_arrangement_reserved_byte;
> +    uint16_t frame_packing_arrangement_repetition_period;
> +
> +    uint8_t  frame_packing_arrangement_extension_flag;
> +} H264RawSEIFramePackingArrangement;
> +
>   typedef struct H264RawSEIDisplayOrientation {
>       uint8_t display_orientation_cancel_flag;
>       uint8_t hor_flip;
> diff --git a/libavcodec/cbs_h2645.c b/libavcodec/cbs_h2645.c
> index 6005d46e0d..0c591871d4 100644
> --- a/libavcodec/cbs_h2645.c
> +++ b/libavcodec/cbs_h2645.c
> @@ -1570,6 +1570,12 @@ static const SEIMessageTypeDescriptor cbs_sei_h264_types[] = {
>           sizeof(H264RawSEIRecoveryPoint),
>           SEI_MESSAGE_RW(h264, sei_recovery_point),
>       },
> +    {
> +        SEI_TYPE_FRAME_PACKING_ARRANGEMENT,
> +        1, 0,
> +        sizeof(H264RawSEIFramePackingArrangement),
> +        SEI_MESSAGE_RW(h264, sei_frame_packing_arrangement),
> +    },
>       {
>           SEI_TYPE_DISPLAY_ORIENTATION,
>           1, 0,
> diff --git a/libavcodec/cbs_h264_syntax_template.c b/libavcodec/cbs_h264_syntax_template.c
> index 9587f33985..e03d41e47a 100644
> --- a/libavcodec/cbs_h264_syntax_template.c
> +++ b/libavcodec/cbs_h264_syntax_template.c
> @@ -719,6 +719,45 @@ static int FUNC(sei_recovery_point)(CodedBitstreamContext *ctx, RWContext *rw,
>       return 0;
>   }
>   
> +
> +
> +static int FUNC(sei_frame_packing_arrangement)
> +    (CodedBitstreamContext *ctx, RWContext *rw,
> +     H264RawSEIFramePackingArrangement *current, SEIMessageState *sei)
> +{
> +    int err;
> +
> +    HEADER("Frame Packing Arrangement");
> +
> +    ue(frame_packing_arrangement_id, 0, UINT32_MAX - 1);
> +    flag(frame_packing_arrangement_cancel_flag);
> +
> +    if (!current->frame_packing_arrangement_cancel_flag) {
> +        u(7, frame_packing_arrangement_type, 0, 7);
> +        flag(quincunx_sampling_flag);
> +        u(6, content_interpretation_type, 0, 2);
> +        flag(spatial_flipping_flag);
> +        flag(frame0_flipped_flag);
> +        flag(field_views_flag);
> +        flag(current_frame_is_frame0_flag);
> +        flag(frame0_self_contained_flag);
> +        flag(frame1_self_contained_flag);
> +        if (!current->quincunx_sampling_flag &&
> +            current->frame_packing_arrangement_type != 5) {

nit: maybe H264_SEI_FPA_TYPE_INTERLEAVE_TEMPORAL instead of 5.

> +            ub(4, frame0_grid_position_x);
> +            ub(4, frame0_grid_position_y);
> +            ub(4, frame1_grid_position_x);
> +            ub(4, frame1_grid_position_y);
> +        }
> +        u(8, frame_packing_arrangement_reserved_byte, 0, 0);
> +        ue(frame_packing_arrangement_repetition_period, 0, 16384);
> +    }
> +
> +    flag(frame_packing_arrangement_extension_flag);
> +
> +    return 0;
> +}
> +
>   static int FUNC(sei_display_orientation)(CodedBitstreamContext *ctx, RWContext *rw,
>                                            H264RawSEIDisplayOrientation *current,
>                                            SEIMessageState *sei)
> 

LGTM.