[FFmpeg-devel] [PATCH] libavutil: AVEncodeInfo data structures and AV_FRAME_DATA_ENCODE_INFO AVFrameSideDataType
James Almer
jamrial at gmail.com
Fri Aug 9 21:02:04 EEST 2019
On 8/9/2019 2:58 PM, Hendrik Leppkes wrote:
> On Fri, Aug 9, 2019 at 7:52 PM James Almer <jamrial at gmail.com> wrote:
>>
>> On 8/9/2019 2:38 PM, Juan De León wrote:
>>> AVEncodeInfoFrame data structure to store as AVFrameSideData of type AV_FRAME_DATA_ENCODE_INFO.
>>> The structure stores quantization index for each plane, DC/AC deltas for luma and chroma planes, and an array of AVEncodeInfoBlock struct denoting position, size, and delta quantizer for each block in the frame.
>>> Can be extended to support extraction of other block information.
>>>
>>> Signed-off-by: Juan De León <juandl at google.com>
>>> ---
>>> fixed a typo in frame.h comment
>>> libavutil/Makefile | 2 +
>>> libavutil/encode_info.c | 67 +++++++++++++++++++++++++++++++
>>> libavutil/encode_info.h | 87 +++++++++++++++++++++++++++++++++++++++++
>>> libavutil/frame.c | 1 +
>>> libavutil/frame.h | 7 ++++
>>> 5 files changed, 164 insertions(+)
>>> create mode 100644 libavutil/encode_info.c
>>> create mode 100644 libavutil/encode_info.h
>>>
>>> diff --git a/libavutil/Makefile b/libavutil/Makefile
>>> index 57e6e3d7e8..37cfb099e9 100644
>>> --- a/libavutil/Makefile
>>> +++ b/libavutil/Makefile
>>> @@ -24,6 +24,7 @@ HEADERS = adler32.h \
>>> dict.h \
>>> display.h \
>>> downmix_info.h \
>>> + encode_info.h \
>>> encryption_info.h \
>>> error.h \
>>> eval.h \
>>> @@ -111,6 +112,7 @@ OBJS = adler32.o \
>>> dict.o \
>>> display.o \
>>> downmix_info.o \
>>> + encode_info.o \
>>> encryption_info.o \
>>> error.o \
>>> eval.o \
>>> diff --git a/libavutil/encode_info.c b/libavutil/encode_info.c
>>> new file mode 100644
>>> index 0000000000..68c30af4d7
>>> --- /dev/null
>>> +++ b/libavutil/encode_info.c
>>> @@ -0,0 +1,67 @@
>>> +/*
>>> + * 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 "libavutil/encode_info.h"
>>> +#include "libavutil/mem.h"
>>> +
>>> +static int init_encode_info_data(AVEncodeInfoFrame *ptr, int nb_blocks) {
>>> + ptr->nb_blocks = nb_blocks;
>>> + ptr->dc_q = ptr->ac_q = -1;
>>> + ptr->dc_chroma_q = ptr->ac_chroma_q = -1;
>>> +
>>> + for(int i=0;i<AV_NUM_DATA_POINTERS;i++)
>>> + ptr->plane_q[i] = -1;
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +AVEncodeInfoFrame *av_encode_info_alloc(int nb_blocks)
>>> +{
>>> + AVEncodeInfoFrame *ptr;
>>> + size_t size = sizeof(AVEncodeInfoFrame) + sizeof(AVEncodeInfoBlock)*nb_blocks;
>>> +
>>> + if (nb_blocks < 0 || size >= INT_MAX)
>>> + return NULL;
>>> +
>>> + ptr = av_mallocz(size);
>>> + if (!ptr)
>>> + return NULL;
>>> +
>>> + init_encode_info_data(ptr, nb_blocks);
>>> +
>>> + return ptr;
>>> +}
>>> +
>>> +AVEncodeInfoFrame *av_encode_info_create_side_data(AVFrame *frame, int nb_blocks)
>>> +{
>>> + size_t size = sizeof(AVEncodeInfoFrame) + sizeof(AVEncodeInfoBlock)*nb_blocks;
>>> +
>>> + if (nb_blocks < 0 || size >= INT_MAX)
>>> + return NULL;
>>> +
>>> + AVFrameSideData *sd = av_frame_new_side_data(frame,
>>> + AV_FRAME_DATA_ENCODE_INFO,
>>> + size);
>>> + if (!sd)
>>> + return NULL;
>>> +
>>> + memset(sd->data, 0, size);
>>> + init_encode_info_data((AVEncodeInfoFrame*)sd->data, nb_blocks);
>>> +
>>> + return (AVEncodeInfoFrame*)sd->data;
>>> +}
>>> diff --git a/libavutil/encode_info.h b/libavutil/encode_info.h
>>> new file mode 100644
>>> index 0000000000..cbe8be2891
>>> --- /dev/null
>>> +++ b/libavutil/encode_info.h
>>> @@ -0,0 +1,87 @@
>>> +/*
>>> + * 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_ENCODE_INFO_H
>>> +#define AVUTIL_ENCODE_INFO_H
>>> +
>>> +#include "libavutil/frame.h"
>>> +
>>> +/**
>>> + * Data structure for extracting block data stored in an array in AVEncodeInfoFrame
>>> + */
>>> +typedef struct AVEncodeInfoBlock{
>>> + /**
>>> + * 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;
>>> + /**
>>> + * Delta quantization index for the block
>>> + */
>>> + int delta_q;
>>> +
>>> + uint8_t reserved[128];
>>> +} AVEncodeInfoBlock;
>>> +
>>> +/**
>>> + * Frame encoding info, used as AVFrameSideData
>>> + */
>>> +typedef struct AVEncodeInfoFrame {
>>> + /**
>>> + * Number of blocks in the array
>>> + */
>>> + int nb_blocks;
>>> + /**
>>> + * Base plane quantizer for the frame, set to -1 when value is unsupported
>>> + */
>>> + int plane_q[AV_NUM_DATA_POINTERS];
>>> + /**
>>> + * DC/AC quantizer index delta, set to -1 when value is value unsupported.
>>> + */
>>> + int ac_q, dc_q;
>>> + /**
>>> + * DC/AC chroma quantizer index delta, set to -1 when value is value unsupported.
>>> + */
>>> + int ac_chroma_q, dc_chroma_q;
>>> +
>>> + uint8_t reserved[256];
>>> +
>>> + AVEncodeInfoBlock blocks[];
>>
>> Flexible array members will break compatibility with C++ projects.
>>
>
> If its the last element in the struct, just make it blocks[1] or
> something and document that dynamically allocated data follows in its
> place. This is common-place even in C++ compatible structs.
> I believe we even use it in some structs ourself.
Or just a pointer that points to the first byte after itself.
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