[FFmpeg-devel] [PATCH 3/6] libavutil: add API for exporting video frame quantizers

Anton Khirnov anton at khirnov.net
Tue Mar 10 19:45:59 EET 2020


From: Juan De León <juandl-at-google.com at ffmpeg.org>

This is intended to replace the deprecated the AV_FRAME_DATA_QP_TABLE*
API and extend it to a wider range of codecs.

In the future, it may also be extended to support other encoding
parameters such as motion vectors.

Signed-off-by: Juan De León <juandl at google.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
Signed-off-by: Anton Khirnov <anton at khirnov.net>
---
 libavutil/Makefile           |   4 +-
 libavutil/frame.c            |   1 +
 libavutil/frame.h            |   5 ++
 libavutil/video_enc_params.c |  81 ++++++++++++++++++++++++
 libavutil/video_enc_params.h | 118 +++++++++++++++++++++++++++++++++++
 5 files changed, 208 insertions(+), 1 deletion(-)
 create mode 100644 libavutil/video_enc_params.c
 create mode 100644 libavutil/video_enc_params.h

diff --git a/libavutil/Makefile b/libavutil/Makefile
index a2dae8e89a..2592f952af 100644
--- a/libavutil/Makefile
+++ b/libavutil/Makefile
@@ -78,6 +78,7 @@ HEADERS = adler32.h                                                     \
           tree.h                                                        \
           twofish.h                                                     \
           version.h                                                     \
+          video_enc_params.h                                            \
           xtea.h                                                        \
           tea.h                                                         \
           tx.h                                                          \
@@ -164,7 +165,8 @@ OBJS = adler32.o                                                        \
        tx.o                                                             \
        tx_float.o                                                       \
        tx_double.o                                                      \
-       tx_int32.o
+       tx_int32.o														\
+       video_enc_params.o
 
 OBJS-$(CONFIG_CUDA)                     += hwcontext_cuda.o
 OBJS-$(CONFIG_D3D11VA)                  += hwcontext_d3d11va.o
diff --git a/libavutil/frame.c b/libavutil/frame.c
index e4038096c2..2f9ba5b6c0 100644
--- a/libavutil/frame.c
+++ b/libavutil/frame.c
@@ -842,6 +842,7 @@ const char *av_frame_side_data_name(enum AVFrameSideDataType type)
 #endif
     case AV_FRAME_DATA_DYNAMIC_HDR_PLUS: return "HDR Dynamic Metadata SMPTE2094-40 (HDR10+)";
     case AV_FRAME_DATA_REGIONS_OF_INTEREST: return "Regions Of Interest";
+    case AV_FRAME_DATA_VIDEO_ENC_PARAMS:            return "Video encoding parameters";
     }
     return NULL;
 }
diff --git a/libavutil/frame.h b/libavutil/frame.h
index b5afb58634..fc67db0f6c 100644
--- a/libavutil/frame.h
+++ b/libavutil/frame.h
@@ -179,6 +179,11 @@ enum AVFrameSideDataType {
      * array element is implied by AVFrameSideData.size / AVRegionOfInterest.self_size.
      */
     AV_FRAME_DATA_REGIONS_OF_INTEREST,
+
+    /**
+     * Encoding parameters for a video frame, as described by AVVideoEncParams.
+     */
+    AV_FRAME_DATA_VIDEO_ENC_PARAMS,
 };
 
 enum AVActiveFormatDescription {
diff --git a/libavutil/video_enc_params.c b/libavutil/video_enc_params.c
new file mode 100644
index 0000000000..4ae088939a
--- /dev/null
+++ b/libavutil/video_enc_params.c
@@ -0,0 +1,81 @@
+/*
+ * 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
+ */
+
+#include <limits.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "buffer.h"
+#include "common.h"
+#include "frame.h"
+#include "mem.h"
+#include "video_enc_params.h"
+
+AVVideoEncParams *av_video_enc_params_alloc(unsigned int nb_blocks, size_t *out_size)
+{
+    AVVideoEncParams *par;
+    size_t size;
+    int i;
+
+    size = sizeof(*par);
+    if (nb_blocks > SIZE_MAX / sizeof(AVVideoBlockParams) ||
+        nb_blocks * sizeof(AVVideoBlockParams) > SIZE_MAX - size)
+        return NULL;
+    size += sizeof(AVVideoBlockParams) * nb_blocks;
+
+    par = av_mallocz(size);
+    if (!par)
+        return NULL;
+
+    par->nb_blocks     = nb_blocks;
+    par->block_size    = sizeof(AVVideoBlockParams);
+    par->blocks_offset = sizeof(*par);
+
+    par->type = AV_VIDEO_ENC_PARAMS_NONE;
+
+    for (i = 0; i < FF_ARRAY_ELEMS(par->qp); i++)
+        par->qp[i] = 0;
+
+    if (out_size)
+        *out_size = size;
+
+    return par;
+}
+
+AVVideoEncParams *av_video_enc_params_create_side_data(AVFrame *frame, unsigned nb_blocks)
+{
+    AVBufferRef      *buf;
+    AVVideoEncParams *par;
+    size_t size;
+
+    par = av_video_enc_params_alloc(nb_blocks, &size);
+    if (!par)
+        return NULL;
+    buf = av_buffer_create((uint8_t *)par, size, NULL, NULL, 0);
+    if (!buf) {
+        av_freep(&par);
+        return NULL;
+    }
+
+    if (!av_frame_new_side_data_from_buf(frame, AV_FRAME_DATA_VIDEO_ENC_PARAMS, buf)) {
+        av_buffer_unref(&buf);
+        return NULL;
+    }
+
+    return par;
+}
diff --git a/libavutil/video_enc_params.h b/libavutil/video_enc_params.h
new file mode 100644
index 0000000000..a7cc4210f3
--- /dev/null
+++ b/libavutil/video_enc_params.h
@@ -0,0 +1,118 @@
+/*
+ * 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,
+};
+
+/**
+ * Data structure for extracting block data, stored as an array in AVEncodeInfoFrame.
+ */
+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 (for each
+     * plane) and the per-frame value.
+     */
+    int delta_qp[4];
+} AVVideoBlockParams;
+
+/**
+ * Video encoding parameters for a given frame. This struct is allocated along
+ * with an 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(AVEncodeInfoBlock).
+     */
+    size_t block_size;
+
+    /**
+     * Type of the parameters (the codec they are used with).
+     */
+    enum AVVideoEncParamsType type;
+
+    /**
+     * Base quantisation parametere for each plane. The final quantiser is a sum
+     * of this value with the per-block value (if it is present).
+     */
+    int qp[4];
+} AVVideoEncParams;
+
+/*
+ * 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 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 of the resulting data array is written here.
+ */
+AVVideoEncParams *av_video_enc_params_alloc(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_ENCODE_INFO
+ * and initializes the variables.
+ */
+AVVideoEncParams *av_video_enc_params_create_side_data(AVFrame *frame, unsigned int nb_blocks);
+
+#endif /* AVUTIL_VIDEO_ENC_PARAMS_H */
-- 
2.24.1



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