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 /**
61  * Video encoding parameters for a given frame. This struct is allocated along
62  * with an optional array of per-block AVVideoBlockParams descriptors.
63  * Must be allocated with av_video_enc_params_alloc().
64  */
65 typedef struct AVVideoEncParams {
66  /**
67  * Number of blocks in the array.
68  *
69  * May be 0, in which case no per-block information is present. In this case
70  * the values of blocks_offset / block_size are unspecified and should not
71  * be accessed.
72  */
73  unsigned int nb_blocks;
74  /**
75  * Offset in bytes from the beginning of this structure at which the array
76  * of blocks starts.
77  */
78  size_t blocks_offset;
79  /*
80  * Size of each block in bytes. May not match sizeof(AVVideoBlockParams).
81  */
82  size_t block_size;
83 
84  /**
85  * Type of the parameters (the codec they are used with).
86  */
88 
89  /**
90  * Base quantisation parameter for the frame. The final quantiser for a
91  * given block in a given plane is obtained from this value, possibly
92  * combined with {@code delta_qp} and the per-block delta in a manner
93  * documented for each type.
94  */
96 
97  /**
98  * Quantisation parameter offset from the base (per-frame) qp for a given
99  * plane (first index) and AC/DC coefficients (second index).
100  */
103 
104 /**
105  * Data structure for storing block-level encoding information.
106  * It is allocated as a part of AVVideoEncParams and should be retrieved with
107  * av_video_enc_params_block().
108  *
109  * sizeof(AVVideoBlockParams) is not a part of the ABI and new fields may be
110  * added to it.
111  */
112 typedef struct AVVideoBlockParams {
113  /**
114  * Distance in luma pixels from the top-left corner of the visible frame
115  * to the top-left corner of the block.
116  * Can be negative if top/right padding is present on the coded frame.
117  */
118  int src_x, src_y;
119  /**
120  * Width and height of the block in luma pixels.
121  */
122  int w, h;
123 
124  /**
125  * Difference between this block's final quantization parameter and the
126  * corresponding per-frame value.
127  */
130 
131 /*
132  * Get the block at the specified {@code idx}. Must be between 0 and nb_blocks.
133  */
136 {
137  av_assert0(idx < par->nb_blocks);
138  return (AVVideoBlockParams *)((uint8_t *)par + par->blocks_offset +
139  idx * par->block_size);
140 }
141 
142 /**
143  * Allocates memory for AVVideoEncParams of the given type, plus an array of
144  * {@code nb_blocks} AVVideoBlockParams and initializes the variables. Can be
145  * freed with a normal av_free() call.
146  *
147  * @param out_size if non-NULL, the size in bytes of the resulting data array is
148  * written here.
149  */
151  unsigned int nb_blocks, size_t *out_size);
152 
153 /**
154  * Allocates memory for AVEncodeInfoFrame plus an array of
155  * {@code nb_blocks} AVEncodeInfoBlock in the given AVFrame {@code frame}
156  * as AVFrameSideData of type AV_FRAME_DATA_VIDEO_ENC_PARAMS
157  * and initializes the variables.
158  */
161  unsigned int nb_blocks);
162 
163 #endif /* AVUTIL_VIDEO_ENC_PARAMS_H */
This structure describes decoded (raw) audio or video data.
Definition: frame.h:308
size_t blocks_offset
Offset in bytes from the beginning of this structure at which the array of blocks starts...
static av_always_inline AVVideoBlockParams * av_video_enc_params_block(AVVideoEncParams *par, unsigned int idx)
int32_t qp
Base quantisation parameter for the frame.
int32_t delta_qp
Difference between this block&#39;s final quantization parameter and the corresponding per-frame value...
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.
GLint GLenum type
Definition: opengl_enc.c:104
int out_size
Definition: movenc.c:55
AVVideoEncParamsType
int32_t delta_qp[4][2]
Quantisation parameter offset from the base (per-frame) qp for a given plane (first index) and AC/DC ...
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
uint8_t
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.
Data structure for storing block-level encoding information.
simple assert() macros that are a bit more flexible than ISO C assert().
enum AVVideoEncParamsType type
Type of the parameters (the codec they are used with).
reference-counted frame API
Video encoding parameters for a given frame.
int w
Width and height of the block in luma pixels.
int32_t
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
unsigned int nb_blocks
Number of blocks in the array.
#define av_always_inline
Definition: attributes.h:45