FFmpeg
video_enc_params.h
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18 
19 #ifndef AVUTIL_VIDEO_ENC_PARAMS_H
20 #define AVUTIL_VIDEO_ENC_PARAMS_H
21 
22 #include <stddef.h>
23 #include <stdint.h>
24 
25 #include "libavutil/avassert.h"
26 #include "libavutil/frame.h"
27 
30  /**
31  * VP9 stores:
32  * - per-frame base (luma AC) quantizer index, exported as AVVideoEncParams.qp
33  * - deltas for luma DC, chroma AC and chroma DC, exported in the
34  * corresponding entries in AVVideoEncParams.delta_qp
35  * - per-segment delta, exported as for each block as AVVideoBlockParams.delta_qp
36  *
37  * To compute the resulting quantizer index for a block:
38  * - for luma AC, add the base qp and the per-block delta_qp, saturating to
39  * unsigned 8-bit.
40  * - for luma DC and chroma AC/DC, add the corresponding
41  * AVVideoBlockParams.delta_qp to the luma AC index, again saturating to
42  * unsigned 8-bit.
43  */
45 
46  /**
47  * H.264 stores:
48  * - in PPS (per-picture):
49  * * initial QP_Y (luma) value, exported as AVVideoEncParams.qp
50  * * delta(s) for chroma QP values (same for both, or each separately),
51  * exported as in the corresponding entries in AVVideoEncParams.delta_qp
52  * - per-slice QP delta, not exported directly, added to the per-MB value
53  * - per-MB delta; not exported directly; the final per-MB quantizer
54  * parameter - QP_Y - minus the value in AVVideoEncParams.qp is exported
55  * as AVVideoBlockParams.qp_delta.
56  */
58 
59  /*
60  * MPEG-2-compatible quantizer.
61  *
62  * Summing the frame-level qp with the per-block delta_qp gives the
63  * resulting quantizer for the block.
64  */
66 };
67 
68 /**
69  * Video encoding parameters for a given frame. This struct is allocated along
70  * with an optional array of per-block AVVideoBlockParams descriptors.
71  * Must be allocated with av_video_enc_params_alloc().
72  */
73 typedef struct AVVideoEncParams {
74  /**
75  * Number of blocks in the array.
76  *
77  * May be 0, in which case no per-block information is present. In this case
78  * the values of blocks_offset / block_size are unspecified and should not
79  * be accessed.
80  */
81  unsigned int nb_blocks;
82  /**
83  * Offset in bytes from the beginning of this structure at which the array
84  * of blocks starts.
85  */
86  size_t blocks_offset;
87  /*
88  * Size of each block in bytes. May not match sizeof(AVVideoBlockParams).
89  */
90  size_t block_size;
91 
92  /**
93  * Type of the parameters (the codec they are used with).
94  */
96 
97  /**
98  * Base quantisation parameter for the frame. The final quantiser for a
99  * given block in a given plane is obtained from this value, possibly
100  * combined with {@code delta_qp} and the per-block delta in a manner
101  * documented for each type.
102  */
104 
105  /**
106  * Quantisation parameter offset from the base (per-frame) qp for a given
107  * plane (first index) and AC/DC coefficients (second index).
108  */
111 
112 /**
113  * Data structure for storing block-level encoding information.
114  * It is allocated as a part of AVVideoEncParams and should be retrieved with
115  * av_video_enc_params_block().
116  *
117  * sizeof(AVVideoBlockParams) is not a part of the ABI and new fields may be
118  * added to it.
119  */
120 typedef struct AVVideoBlockParams {
121  /**
122  * Distance in luma pixels from the top-left corner of the visible frame
123  * to the top-left corner of the block.
124  * Can be negative if top/right padding is present on the coded frame.
125  */
126  int src_x, src_y;
127  /**
128  * Width and height of the block in luma pixels.
129  */
130  int w, h;
131 
132  /**
133  * Difference between this block's final quantization parameter and the
134  * corresponding per-frame value.
135  */
138 
139 /*
140  * Get the block at the specified {@code idx}. Must be between 0 and nb_blocks.
141  */
144 {
145  av_assert0(idx < par->nb_blocks);
146  return (AVVideoBlockParams *)((uint8_t *)par + par->blocks_offset +
147  idx * par->block_size);
148 }
149 
150 /**
151  * Allocates memory for AVVideoEncParams of the given type, plus an array of
152  * {@code nb_blocks} AVVideoBlockParams and initializes the variables. Can be
153  * freed with a normal av_free() call.
154  *
155  * @param out_size if non-NULL, the size in bytes of the resulting data array is
156  * written here.
157  */
159  unsigned int nb_blocks, size_t *out_size);
160 
161 /**
162  * Allocates memory for AVEncodeInfoFrame plus an array of
163  * {@code nb_blocks} AVEncodeInfoBlock in the given AVFrame {@code frame}
164  * as AVFrameSideData of type AV_FRAME_DATA_VIDEO_ENC_PARAMS
165  * and initializes the variables.
166  */
169  unsigned int nb_blocks);
170 
171 #endif /* AVUTIL_VIDEO_ENC_PARAMS_H */
AVVideoEncParams::qp
int32_t qp
Base quantisation parameter for the frame.
Definition: video_enc_params.h:103
AVVideoEncParams::blocks_offset
size_t blocks_offset
Offset in bytes from the beginning of this structure at which the array of blocks starts.
Definition: video_enc_params.h:86
AV_VIDEO_ENC_PARAMS_NONE
@ AV_VIDEO_ENC_PARAMS_NONE
Definition: video_enc_params.h:29
out_size
int out_size
Definition: movenc.c:55
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:324
AVVideoBlockParams::src_x
int src_x
Distance in luma pixels from the top-left corner of the visible frame to the top-left corner of the b...
Definition: video_enc_params.h:126
av_video_enc_params_create_side_data
AVVideoEncParams * av_video_enc_params_create_side_data(AVFrame *frame, enum AVVideoEncParamsType type, unsigned int nb_blocks)
Allocates memory for AVEncodeInfoFrame plus an array of.
Definition: video_enc_params.c:56
AV_VIDEO_ENC_PARAMS_MPEG2
@ AV_VIDEO_ENC_PARAMS_MPEG2
Definition: video_enc_params.h:65
AVVideoBlockParams::src_y
int src_y
Definition: video_enc_params.h:126
AVVideoEncParams::delta_qp
int32_t delta_qp[4][2]
Quantisation parameter offset from the base (per-frame) qp for a given plane (first index) and AC/DC ...
Definition: video_enc_params.h:109
AVVideoBlockParams::delta_qp
int32_t delta_qp
Difference between this block's final quantization parameter and the corresponding per-frame value.
Definition: video_enc_params.h:136
AV_VIDEO_ENC_PARAMS_H264
@ AV_VIDEO_ENC_PARAMS_H264
H.264 stores:
Definition: video_enc_params.h:57
type
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf type
Definition: writing_filters.txt:86
AVVideoEncParams
Video encoding parameters for a given frame.
Definition: video_enc_params.h:73
avassert.h
AVVideoEncParamsType
AVVideoEncParamsType
Definition: video_enc_params.h:28
av_assert0
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
AVVideoEncParams::type
enum AVVideoEncParamsType type
Type of the parameters (the codec they are used with).
Definition: video_enc_params.h:95
int32_t
int32_t
Definition: audio_convert.c:194
AVVideoEncParams::block_size
size_t block_size
Definition: video_enc_params.h:90
AVVideoBlockParams::h
int h
Definition: video_enc_params.h:130
AVVideoBlockParams::w
int w
Width and height of the block in luma pixels.
Definition: video_enc_params.h:130
AVVideoEncParams::nb_blocks
unsigned int nb_blocks
Number of blocks in the array.
Definition: video_enc_params.h:81
frame.h
av_always_inline
#define av_always_inline
Definition: attributes.h:49
uint8_t
uint8_t
Definition: audio_convert.c:194
AVVideoBlockParams
Data structure for storing block-level encoding information.
Definition: video_enc_params.h:120
frame
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
Definition: filter_design.txt:264
av_video_enc_params_alloc
AVVideoEncParams * av_video_enc_params_alloc(enum AVVideoEncParamsType type, unsigned int nb_blocks, size_t *out_size)
Allocates memory for AVVideoEncParams of the given type, plus an array of.
Definition: video_enc_params.c:29
AV_VIDEO_ENC_PARAMS_VP9
@ AV_VIDEO_ENC_PARAMS_VP9
VP9 stores:
Definition: video_enc_params.h:44
av_video_enc_params_block
static av_always_inline AVVideoBlockParams * av_video_enc_params_block(AVVideoEncParams *par, unsigned int idx)
Definition: video_enc_params.h:143