On 05/12/2018 09:58, Guo, Yejun wrote:
> this patch is not ask for merge, it is more to get a feature feedback.
>
> The encoders such as libx264 support different QPs offset for different MBs,
> it makes possible for ROI-based encoding. It makes sense to add support
> within ffmpeg to generate/accept ROI infos and pass into encoders.
>
> Typical usage: After AVFrame is decoded, a ffmpeg filter or user's code
> generates ROI info for that frame, and the encoder finally does the
> ROI-based encoding. And so I choose to maintain the ROI info within
> AVFrame struct.
>
> TODO:
> - remove code in vf_scale.c, it is just an example to generate ROI info
> - use AVBufferRef instead of current implementation within AVFrame struct.
> - add other encoders support
>
> Signed-off-by: Guo, Yejun <yejun....@intel.com>
> ---
> libavcodec/libx264.c | 35 +++++++++++++++++++++++++++++++++++
> libavfilter/vf_scale.c | 8 ++++++++
> libavutil/frame.c | 9 +++++++++
> libavutil/frame.h | 14 ++++++++++++++
> 4 files changed, 66 insertions(+)
This approach seems reasonable to me; some thoughts below.
> ...
> diff --git a/libavutil/frame.c b/libavutil/frame.c
> index 9b3fb13..9c38bdd 100644
> --- a/libavutil/frame.c
> +++ b/libavutil/frame.c
> @@ -425,6 +425,15 @@ FF_DISABLE_DEPRECATION_WARNINGS
> FF_ENABLE_DEPRECATION_WARNINGS
> #endif
>
> + dst->nb_rois = src->nb_rois;
> + for (int i = 0; i < dst->nb_rois; ++i) {
> + dst->rois[i].top = src->rois[i].top;
> + dst->rois[i].bottom = src->rois[i].bottom;
> + dst->rois[i].left = src->rois[i].left;
> + dst->rois[i].right = src->rois[i].right;
> + dst->rois[i].qoffset = src->rois[i].qoffset;
> + }
> +
> av_buffer_unref(&dst->opaque_ref);
> av_buffer_unref(&dst->private_ref);
> if (src->opaque_ref) {
> diff --git a/libavutil/frame.h b/libavutil/frame.h
> index 66f27f4..b245a90 100644
> --- a/libavutil/frame.h
> +++ b/libavutil/frame.h
> @@ -193,6 +193,15 @@ typedef struct AVFrameSideData {
> AVBufferRef *buf;
> } AVFrameSideData;
>
> +
> +typedef struct AVFrameROI {
> + size_t top;
> + size_t bottom;
> + size_t left;
> + size_t right;
Do you want some additional constraints on this? For example, must be integers
in every plane (so even values only for 4:2:0), or maybe even must match some
codec-specific block size.
> + float qoffset;
Everything else uses integers here, so this should be an integer. The meaning
of it will probably be entirely codec-dependent.
> +} AVFrameROI;
> +
> /**
> * This structure describes decoded (raw) audio or video data.
> *
> @@ -556,6 +565,11 @@ typedef struct AVFrame {
> attribute_deprecated
> AVBufferRef *qp_table_buf;
> #endif
> +
> + //TODO: AVBufferRef*
> + AVFrameROI rois[2];
> + size_t nb_rois;
This should be side-data (which is automatically refcounted) rather than
included directly in the AVFrame.
> +
> /**
> * For hwaccel-format frames, this should be a reference to the
> * AVHWFramesContext describing the frame.
>
Thanks,
- Mark
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