[FFmpeg-devel] [PATCH 2/2] lavc/d3d12va_encode: trim header alignment at output

[Tong Wu]

Tong Wu:
>Subject: [FFmpeg-devel][PATCH 2/2] lavc/d3d12va_encode: trim header
>alignment at output
>
>It is d3d12va's requirement that the FrameStartOffset must be aligned as per
>hardware limitation. However, we could trim this alignment at output to reduce
>coded size. A aligned_header_size is added to D3D12VAEncodePicture.
>
>Signed-off-by: Tong Wu <wutong1208 at outlook.com>
>---
> libavcodec/d3d12va_encode.c | 18 ++++++++++++------
>libavcodec/d3d12va_encode.h |  1 +
> 2 files changed, 13 insertions(+), 6 deletions(-)
>
>diff --git a/libavcodec/d3d12va_encode.c b/libavcodec/d3d12va_encode.c index
>9f7a42911e..9ee9da41e3 100644
>--- a/libavcodec/d3d12va_encode.c
>+++ b/libavcodec/d3d12va_encode.c
>@@ -308,9 +308,9 @@ static int d3d12va_encode_issue(AVCodecContext *avctx,
>         }
>
>         pic->header_size = (int)bit_len / 8;
>-        pic->header_size = pic->header_size % ctx-
>>req.CompressedBitstreamBufferAccessAlignment ?
>-                           FFALIGN(pic->header_size, ctx-
>>req.CompressedBitstreamBufferAccessAlignment) :
>-                           pic->header_size;
>+        pic->aligned_header_size = pic->header_size % ctx-
>>req.CompressedBitstreamBufferAccessAlignment ?
>+                                   FFALIGN(pic->header_size, ctx-
>>req.CompressedBitstreamBufferAccessAlignment) :
>+                                   pic->header_size;
>
>         hr = ID3D12Resource_Map(pic->output_buffer, 0, NULL, (void **)&ptr);
>         if (FAILED(hr)) {
>@@ -318,7 +318,7 @@ static int d3d12va_encode_issue(AVCodecContext *avctx,
>             goto fail;
>         }
>
>-        memcpy(ptr, data, pic->header_size);
>+        memcpy(ptr, data, pic->aligned_header_size);
>         ID3D12Resource_Unmap(pic->output_buffer, 0, NULL);
>     }
>
>@@ -344,10 +344,10 @@ static int d3d12va_encode_issue(AVCodecContext
>*avctx,
>
>     input_args.PictureControlDesc.PictureControlCodecData = pic->pic_ctl;
>     input_args.PictureControlDesc.ReferenceFrames         = d3d12_refs;
>-    input_args.CurrentFrameBitstreamMetadataSize          = pic->header_size;
>+    input_args.CurrentFrameBitstreamMetadataSize          = pic-
>>aligned_header_size;
>
>     output_args.Bitstream.pBuffer                                    = pic->output_buffer;
>-    output_args.Bitstream.FrameStartOffset                           = pic->header_size;
>+    output_args.Bitstream.FrameStartOffset                           = pic-
>>aligned_header_size;
>     output_args.ReconstructedPicture.pReconstructedPicture           = pic-
>>recon_surface->texture;
>     output_args.ReconstructedPicture.ReconstructedPictureSubresource = 0;
>     output_args.EncoderOutputMetadata.pBuffer                        = pic-
>>encoded_metadata;
>@@ -663,6 +663,12 @@ static int
>d3d12va_encode_get_coded_data(AVCodecContext *avctx,
>         goto end;
>     ptr = pkt->data;
>
>+    memcpy(ptr, mapped_data, pic->header_size);
>+
>+    ptr += pic->header_size;
>+    mapped_data += pic->aligned_header_size;
>+    total_size -= pic->header_size;
>+
>     memcpy(ptr, mapped_data, total_size);
>
>     ID3D12Resource_Unmap(pic->output_buffer, 0, NULL); diff --git
>a/libavcodec/d3d12va_encode.h b/libavcodec/d3d12va_encode.h index
>1a0abc5bd0..51440428e4 100644
>--- a/libavcodec/d3d12va_encode.h
>+++ b/libavcodec/d3d12va_encode.h
>@@ -43,6 +43,7 @@ typedef struct D3D12VAEncodePicture {
>     FFHWBaseEncodePicture base;
>
>     int             header_size;
>+    int             aligned_header_size;
>
>     AVD3D12VAFrame *input_surface;
>     AVD3D12VAFrame *recon_surface;
>--
>2.45.1.windows.1


The first patch in this patchset has been merged earlier. Will merge this patch if there's no more comment.

-Tong