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+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVUTIL_VIDEO_ENC_PARAMS_H
+#define AVUTIL_VIDEO_ENC_PARAMS_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "libavutil/avassert.h"
+#include "libavutil/frame.h"
+
+enum AVVideoEncParamsType {
+ AV_VIDEO_ENC_PARAMS_NONE = -1,
+ /**
+ * VP9 stores:
+ * - per-frame base (luma AC) quantizer index, exported as AVVideoEncParams.qp
+ * - deltas for luma DC, chroma AC and chroma DC, exported in the
+ * corresponding entries in AVVideoEncParams.delta_qp
+ * - per-segment delta, exported as for each block as AVVideoBlockParams.delta_qp
+ *
+ * To compute the resulting quantizer index for a block:
+ * - for luma AC, add the base qp and the per-block delta_qp, saturating to
+ * unsigned 8-bit.
+ * - for luma DC and chroma AC/DC, add the corresponding
+ * AVVideoBlockParams.delta_qp to the luma AC index, again saturating to
+ * unsigned 8-bit.
+ */
+ AV_VIDEO_ENC_PARAMS_VP9,
+
+ /**
+ * H.264 stores:
+ * - in PPS (per-picture):
+ * * initial QP_Y (luma) value, exported as AVVideoEncParams.qp
+ * * delta(s) for chroma QP values (same for both, or each separately),
+ * exported as in the corresponding entries in AVVideoEncParams.delta_qp
+ * - per-slice QP delta, not exported directly, added to the per-MB value
+ * - per-MB delta; not exported directly; the final per-MB quantizer
+ * parameter - QP_Y - minus the value in AVVideoEncParams.qp is exported
+ * as AVVideoBlockParams.qp_delta.
+ */
+ AV_VIDEO_ENC_PARAMS_H264,
+
+ /*
+ * MPEG-2-compatible quantizer.
+ *
+ * Summing the frame-level qp with the per-block delta_qp gives the
+ * resulting quantizer for the block.
+ */
+ AV_VIDEO_ENC_PARAMS_MPEG2,
+};
+
+/**
+ * Video encoding parameters for a given frame. This struct is allocated along
+ * with an optional array of per-block AVVideoBlockParams descriptors.
+ * Must be allocated with av_video_enc_params_alloc().
+ */
+typedef struct AVVideoEncParams {
+ /**
+ * Number of blocks in the array.
+ *
+ * May be 0, in which case no per-block information is present. In this case
+ * the values of blocks_offset / block_size are unspecified and should not
+ * be accessed.
+ */
+ unsigned int nb_blocks;
+ /**
+ * Offset in bytes from the beginning of this structure at which the array
+ * of blocks starts.
+ */
+ size_t blocks_offset;
+ /*
+ * Size of each block in bytes. May not match sizeof(AVVideoBlockParams).
+ */
+ size_t block_size;
+
+ /**
+ * Type of the parameters (the codec they are used with).
+ */
+ enum AVVideoEncParamsType type;
+
+ /**
+ * Base quantisation parameter for the frame. The final quantiser for a
+ * given block in a given plane is obtained from this value, possibly
+ * combined with {@code delta_qp} and the per-block delta in a manner
+ * documented for each type.
+ */
+ int32_t qp;
+
+ /**
+ * Quantisation parameter offset from the base (per-frame) qp for a given
+ * plane (first index) and AC/DC coefficients (second index).
+ */
+ int32_t delta_qp[4][2];
+} AVVideoEncParams;
+
+/**
+ * Data structure for storing block-level encoding information.
+ * It is allocated as a part of AVVideoEncParams and should be retrieved with
+ * av_video_enc_params_block().
+ *
+ * sizeof(AVVideoBlockParams) is not a part of the ABI and new fields may be
+ * added to it.
+ */
+typedef struct AVVideoBlockParams {
+ /**
+ * Distance in luma pixels from the top-left corner of the visible frame
+ * to the top-left corner of the block.
+ * Can be negative if top/right padding is present on the coded frame.
+ */
+ int src_x, src_y;
+ /**
+ * Width and height of the block in luma pixels.
+ */
+ int w, h;
+
+ /**
+ * Difference between this block's final quantization parameter and the
+ * corresponding per-frame value.
+ */
+ int32_t delta_qp;
+} AVVideoBlockParams;
+
+/*
+ * Get the block at the specified {@code idx}. Must be between 0 and nb_blocks.
+ */
+static av_always_inline AVVideoBlockParams*
+av_video_enc_params_block(AVVideoEncParams *par, unsigned int idx)
+{
+ av_assert0(idx < par->nb_blocks);
+ return (AVVideoBlockParams *)((uint8_t *)par + par->blocks_offset +
+ idx * par->block_size);
+}
+
+/**
+ * Allocates memory for AVVideoEncParams of the given type, plus an array of
+ * {@code nb_blocks} AVVideoBlockParams and initializes the variables. Can be
+ * freed with a normal av_free() call.
+ *
+ * @param out_size if non-NULL, the size in bytes of the resulting data array is
+ * written here.
+ */
+AVVideoEncParams *av_video_enc_params_alloc(enum AVVideoEncParamsType type,
+ unsigned int nb_blocks, size_t *out_size);
+
+/**
+ * Allocates memory for AVEncodeInfoFrame plus an array of
+ * {@code nb_blocks} AVEncodeInfoBlock in the given AVFrame {@code frame}
+ * as AVFrameSideData of type AV_FRAME_DATA_VIDEO_ENC_PARAMS
+ * and initializes the variables.
+ */
+AVVideoEncParams*
+av_video_enc_params_create_side_data(AVFrame *frame, enum AVVideoEncParamsType type,
+ unsigned int nb_blocks);
+
+#endif /* AVUTIL_VIDEO_ENC_PARAMS_H */