FFmpeg
qp_table.h
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18 
19 #ifndef AVFILTER_QP_TABLE_H
20 #define AVFILTER_QP_TABLE_H
21 
22 #include <stdint.h>
23 
24 #include "libavutil/frame.h"
25 #include "libavcodec/internal.h"
26 
27 /**
28  * Extract a libpostproc-compatible QP table - an 8-bit QP value per 16x16
29  * macroblock, stored in raster order - from AVVideoEncParams side data.
30  */
31 int ff_qp_table_extract(AVFrame *frame, int8_t **table, int *table_w, int *table_h,
32  int *qscale_type);
33 
34 /**
35  * Normalize the qscale factor
36  * FIXME the H264 qscale is a log based scale, mpeg1/2 is not, the code below
37  * cannot be optimal
38  */
39 static inline int ff_norm_qscale(int qscale, int type)
40 {
41  switch (type) {
42  case FF_QSCALE_TYPE_MPEG1: return qscale;
43  case FF_QSCALE_TYPE_MPEG2: return qscale >> 1;
44  case FF_QSCALE_TYPE_H264: return qscale >> 2;
45  case FF_QSCALE_TYPE_VP56: return (63 - qscale + 2) >> 2;
46  }
47  return qscale;
48 }
49 
50 #endif // AVFILTER_QP_TABLE_H
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:317
internal.h
table
static const uint16_t table[]
Definition: prosumer.c:206
ff_norm_qscale
static int ff_norm_qscale(int qscale, int type)
Normalize the qscale factor FIXME the H264 qscale is a log based scale, mpeg1/2 is not,...
Definition: qp_table.h:39
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
FF_QSCALE_TYPE_MPEG2
#define FF_QSCALE_TYPE_MPEG2
Definition: internal.h:97
ff_qp_table_extract
int ff_qp_table_extract(AVFrame *frame, int8_t **table, int *table_w, int *table_h, int *qscale_type)
Extract a libpostproc-compatible QP table - an 8-bit QP value per 16x16 macroblock,...
Definition: qp_table.c:30
FF_QSCALE_TYPE_MPEG1
#define FF_QSCALE_TYPE_MPEG1
Definition: internal.h:96
frame.h
FF_QSCALE_TYPE_H264
#define FF_QSCALE_TYPE_H264
Definition: internal.h:98
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
FF_QSCALE_TYPE_VP56
#define FF_QSCALE_TYPE_VP56
Definition: internal.h:99
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