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documenting most stuff in AVCodecContext

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Originally committed as revision 957 to svn://svn.ffmpeg.org/ffmpeg/trunk
pull/126/head
Michael Niedermayer 23 years ago
parent 0af65aac18
commit b71901e6ee
1 changed files with 372 additions and 65 deletions
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  1. 437
      libavcodec/avcodec.h

437
libavcodec/avcodec.h
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@ -105,27 +105,27 @@ static const int Motion_Est_QTab[] = { ME_ZERO, ME_PHODS, ME_LOG,
Note: note not everything is supported yet
*/
#define CODEC_FLAG_HQ 0x0001 /* high quality (non real time) encoding */
#define CODEC_FLAG_QSCALE 0x0002 /* use fixed qscale */
#define CODEC_FLAG_4MV 0x0004 /* 4 MV per MB allowed */
#define CODEC_FLAG_QPEL 0x0010 /* use qpel MC */
#define CODEC_FLAG_GMC 0x0020 /* use GMC */
#define CODEC_FLAG_TYPE 0x0040 /* fixed I/P frame type, from avctx->key_frame */
#define CODEC_FLAG_PART 0x0080 /* use data partitioning */
#define CODEC_FLAG_HQ 0x0001 /* brute force MB-type decission mode (slow) */
#define CODEC_FLAG_QSCALE 0x0002 /* use fixed qscale */
#define CODEC_FLAG_4MV 0x0004 /* 4 MV per MB allowed */
#define CODEC_FLAG_QPEL 0x0010 /* use qpel MC */
#define CODEC_FLAG_GMC 0x0020 /* use GMC */
#define CODEC_FLAG_TYPE 0x0040 /* fixed I/P frame type, from avctx->key_frame */
#define CODEC_FLAG_PART 0x0080 /* use data partitioning */
/* parent program gurantees that the input for b-frame containing streams is not written to
for at least s->max_b_frames+1 frames, if this is not set than the input will be copied */
#define CODEC_FLAG_INPUT_PRESERVED 0x0100
#define CODEC_FLAG_PASS1 0x0200 /* use internal 2pass ratecontrol in first pass mode */
#define CODEC_FLAG_PASS2 0x0400 /* use internal 2pass ratecontrol in second pass mode */
#define CODEC_FLAG_PASS1 0x0200 /* use internal 2pass ratecontrol in first pass mode */
#define CODEC_FLAG_PASS2 0x0400 /* use internal 2pass ratecontrol in second pass mode */
#define CODEC_FLAG_EXTERN_HUFF 0x1000 /* use external huffman table (for mjpeg) */
#define CODEC_FLAG_GRAY 0x2000 /* only decode/encode grayscale */
#define CODEC_FLAG_GRAY 0x2000 /* only decode/encode grayscale */
#define CODEC_FLAG_EMU_EDGE 0x4000/* dont draw edges */
#define CODEC_FLAG_DR1 0x8000 /* dr1 */
#define CODEC_FLAG_NOT_TRUNCATED 0x00010000 /* input bitstream is not truncated, except before a startcode */
#define CODEC_FLAG_DR1 0x8000 /* direct renderig type 1 (store internal frames in external buffers) */
#define CODEC_FLAG_NOT_TRUNCATED 0x00010000 /* input bitstream is not truncated, except before a startcode
allows the last part of a frame to be decoded earlier */
/* codec capabilities */
/* decoder can use draw_horiz_band callback */
#define CODEC_CAP_DRAW_HORIZ_BAND 0x0001
#define CODEC_CAP_DRAW_HORIZ_BAND 0x0001 /* decoder can use draw_horiz_band callback */
#define CODEC_CAP_DR1 0x0002 /* direct rendering method 1 */
/* if 'parse_only' field is true, then avcodec_parse_frame() can be
used */
@ -134,23 +134,72 @@ static const int Motion_Est_QTab[] = { ME_ZERO, ME_PHODS, ME_LOG,
#define FRAME_RATE_BASE 10000
typedef struct AVCodecContext {
/**
* the average bitrate
* encoding: set by user. unused for constant quantizer encoding
* decoding: set by lavc. 0 or some bitrate if this info is available in the stream
*/
int bit_rate;
int bit_rate_tolerance; /* amount of +- bits (>0)*/
/**
* number of bits the bitstream is allowed to diverge from the reference
* the reference can be CBR (for CBR pass1) or VBR (for pass2)
* encoding: set by user. unused for constant quantizer encoding
* decoding: unused
*/
int bit_rate_tolerance;
/**
* CODEC_FLAG_*
* encoding: set by user.
* decoding: set by user.
*/
int flags;
int sub_id; /* some codecs needs additionnal format info. It is
stored there */
int me_method; /* ME algorithm used for video coding */
/* extra data from parent application to codec, e.g. huffman table
for mjpeg */
/* the parent should allocate and free this buffer */
/**
* some codecs needs additionnal format info. It is stored here
* encoding: set by user.
* decoding: set by lavc. (FIXME is this ok?)
*/
int sub_id;
/**
* motion estimation algorithm used for video coding
* encoding: set by user.
* decoding: unused
*/
int me_method;
/**
* some codecs need / can use extra-data like huffman tables
* mjpeg: huffman tables
* rv10: additional flags
* encoding: set/allocated/freed by user.
* decoding: set/allocated/freed by lavc. (can be NULL)
*/
void *extradata;
int extradata_size;
/* video only */
int frame_rate; /* frames per sec multiplied by FRAME_RATE_BASE */
/**
* frames per sec multiplied by FRAME_RATE_BASE
* for variable fps this is the precission, so if the timestamps
* can be specified in msec precssion then this is 1000*FRAME_RATE_BASE
* encoding: set by user
* decoding: set by lavc. 0 or the frame_rate if available
*/
int frame_rate;
/**
* encoding: set by user.
* decoding: set by user, some codecs might override / change it during playback
*/
int width, height;
/**
* encoding: set by user. 0 if not known
* decoding: set by lavc. 0 if not known
*/
int aspect_ratio_info;
#define FF_ASPECT_SQUARE 1
#define FF_ASPECT_4_3_625 2
@ -158,15 +207,33 @@ typedef struct AVCodecContext {
#define FF_ASPECT_16_9_625 4
#define FF_ASPECT_16_9_525 5
#define FF_ASPECT_EXTENDED 15
int gop_size; /* 0 = intra only */
enum PixelFormat pix_fmt; /* pixel format, see PIX_FMT_xxx */
/**
* the number of pictures in a group of pitures, or 0 for intra_only
* encoding: set by user.
* decoding: unused
*/
int gop_size;
/**
* pixel format, see PIX_FMT_xxx
* encoding: unused
* decoding: set by lavc.
*/
enum PixelFormat pix_fmt;
int repeat_pict; /* when decoding, this signal how much the picture */
/* must be delayed. */
/* extra_delay = (repeat_pict / 2) * (1/fps) */
/* if non NULL, 'draw_horiz_band' is called by the libavcodec
decoder to draw an horizontal band. It improve cache usage. Not
all codecs can do that. You must check the codec capabilities
before */
/**
* if non NULL, 'draw_horiz_band' is called by the libavcodec
* decoder to draw an horizontal band. It improve cache usage. Not
* all codecs can do that. You must check the codec capabilities
* before
* encoding: unused
* decoding: set by user.
*/
void (*draw_horiz_band)(struct AVCodecContext *s,
UINT8 **src_ptr, int linesize,
int y, int width, int height);
@ -181,20 +248,41 @@ typedef struct AVCodecContext {
int frame_number; /* audio or video frame number */
int real_pict_num; /* returns the real picture number of
previous encoded frame */
int key_frame; /* true if the previous compressed frame was
a key frame (intra, or seekable) */
int pict_type; /* picture type of the previous
en/decoded frame */
/**
* 1 -> keyframe, 0-> not
* encoding: set by lavc (for the outputed bitstream, not the input frame)
* decoding: set by lavc (for the decoded bitstream, not the displayed frame)
*/
int key_frame;
/**
* picture type of the previous en/decoded frame, see ?_TYPE below
* encoding: set by lavc (for the outputed bitstream, not the input frame)
* decoding: set by lavc (for the decoded bitstream, not the displayed frame)
*/
int pict_type;
/* FIXME: these should have FF_ */
#define I_TYPE 1 // Intra
#define P_TYPE 2 // Predicted
#define B_TYPE 3 // Bi-dir predicted
#define S_TYPE 4 // S(GMC)-VOP MPEG4
int delay; /* number of frames the decoded output
will be delayed relative to the encoded input */
uint8_t *mbskip_table; /* =1 if MB didnt change, is only valid for I/P frames
stride= mb_width = (width+15)>>4 */
/**
* number of frames the decoded output will be delayed relative to
* the encoded input
* encoding: set by lavc.
* decoding: unused
*/
int delay;
/**
* mbskip_table[mb]=1 if MB didnt change, is only valid for I/P frames
* stride= mb_width = (width+15)>>4 (FIXME export stride?)
* encoding: unused
* decoding: set by lavc
*/
uint8_t *mbskip_table;
/* encoding parameters */
int quality; /* quality of the previous encoded frame
@ -203,18 +291,55 @@ typedef struct AVCodecContext {
and the per frame quality in CODEC_FLAG_TYPE (second pass mode) */
float qcompress; /* amount of qscale change between easy & hard scenes (0.0-1.0)*/
float qblur; /* amount of qscale smoothing over time (0.0-1.0) */
int qmin; /* min qscale */
int qmax; /* max qscale */
int max_qdiff; /* max qscale difference between frames */
int max_b_frames; /* maximum b frames, the output will be delayed by max_b_frames+1 relative to the input */
float b_quant_factor;/* qscale factor between ps and b frames */
int rc_strategy; /* obsolete FIXME remove */
/**
* minimum quantizer
* encoding: set by user.
* decoding: unused
*/
int qmin;
/**
* maximum quantizer
* encoding: set by user.
* decoding: unused
*/
int qmax;
/**
* maximum quantizer difference etween frames
* encoding: set by user.
* decoding: unused
*/
int max_qdiff;
/**
* maximum number of b frames between non b frames
* note: the output will be delayed by max_b_frames+1 relative to the input
* encoding: set by user.
* decoding: unused
*/
int max_b_frames;
/**
* qscale factor between ip and b frames
* encoding: set by user.
* decoding: unused
*/
float b_quant_factor;
/** obsolete FIXME remove */
int rc_strategy;
int b_frame_strategy;
int hurry_up; /* when set to 1 during decoding, b frames will be skiped
when set to 2 idct/dequant will be skipped too */
/**
* encoding: unused
* decoding: set by user. 1-> skip b frames, 2-> skip idct/dequant too
*/
int hurry_up;
struct AVCodec *codec;
void *priv_data;
/* The following data is for RTP friendly coding */
@ -237,8 +362,12 @@ typedef struct AVCodecContext {
/* with a Start Code (it should) H.263 does */
void (*rtp_callback)(void *data, int size, int packet_number);
/* These are for PSNR calculation, if you set get_psnr to 1 */
/* after encoding you will have the PSNR on psnr_y/cb/cr */
/**
* if you set get_psnr to 1 then after encoding you will have the
* PSNR on psnr_y/cb/cr
* encoding: set by user (1-> on, 0-> off)
* decoding: unused
*/
int get_psnr;
float psnr_y;
float psnr_cb;
@ -252,21 +381,66 @@ typedef struct AVCodecContext {
int i_count;
int p_count;
int skip_count;
int misc_bits; // cbp, mb_type
int misc_bits;
/**
* number of bits used for the previously encoded frame
* encoding: set by lavc
* decoding: unused
*/
int frame_bits;
/* the following fields are ignored */
void *opaque; /* can be used to carry app specific stuff */
/**
* private data of the user, can be used to carry app specific stuff
* encoding: set by user
* decoding: set by user
*/
void *opaque;
char codec_name[32];
enum CodecType codec_type; /* see CODEC_TYPE_xxx */
enum CodecID codec_id; /* see CODEC_ID_xxx */
unsigned int codec_tag; /* codec tag, only used if unknown codec */
int workaround_bugs; /* workaround bugs in encoders which cannot be detected automatically */
/**
* workaround bugs in encoders which cannot be detected automatically
* encoding: unused
* decoding: set by user
*/
int workaround_bugs;
/**
* encoding: set by user
* decoding: unused
*/
int luma_elim_threshold;
/**
* encoding: set by user
* decoding: unused
*/
int chroma_elim_threshold;
int strict_std_compliance; /* strictly follow the std (MPEG4, ...) */
float b_quant_offset;/* qscale offset between ips and b frames, not implemented yet */
/**
* strictly follow the std (MPEG4, ...)
* encoding: set by user
* decoding: unused
*/
int strict_std_compliance;
/**
* qscale offset between ip and b frames
* encoding: set by user.
* decoding: unused
*/
float b_quant_offset;
/**
* error resilience {-1,0,1} higher values will detect more errors but may missdetect
* some more or less valid parts as errors
* encoding: unused
* decoding: set by user
*/
int error_resilience;
#ifndef MBC
@ -278,41 +452,168 @@ typedef struct AVCodecContext {
QP_TYPE *quant_store; /* field for communicating with external postprocessing */
unsigned qstride;
/**
* buffer, where the next picture should be decoded into
* encoding: unused
* decoding: set by user in get_buffer_callback to a buffer into which the next part
* of the bitstream will be decoded, and set by lavc at end of frame to the
* next frame which needs to be displayed
*/
uint8_t *dr_buffer[3];
/**
* stride of the luminance part of the dr buffer
* encoding: unused
* decoding: set by user
*/
int dr_stride;
/**
* same behavior as dr_buffer, just for some private data of the user
* encoding: unused
* decoding: set by user in get_buffer_callback, and set by lavc at end of frame
*/
void *dr_opaque_frame;
/**
* called at the beginning of each frame to get a buffer for it
* encoding: unused
* decoding: set by user
*/
void (*get_buffer_callback)(struct AVCodecContext *c, int width, int height, int pict_type);
int has_b_frames; // is 1 if the decoded stream contains b frames
/**
* is 1 if the decoded stream contains b frames, 0 otherwise
* encoding: unused
* decoding: set by lavc
*/
int has_b_frames;
/**
* stride of the chrominance part of the dr buffer
* encoding: unused
* decoding: set by user
*/
int dr_uvstride;
/**
* number of dr buffers
* encoding: unused
* decoding: set by user
*/
int dr_ip_buffer_count;
int block_align; /* currently only for adpcm codec in wav/avi */
int parse_only; /* decoding only: if true, only parsing is done
(function avcodec_parse_frame()). The frame
data is returned. Only MPEG codecs support this now. */
int mpeg_quant; /* 0-> h263 quant 1-> mpeg quant */
/**
* 0-> h263 quant 1-> mpeg quant
* encoding: set by user.
* decoding: unused
*/
int mpeg_quant;
/**
* pass1 encoding statistics output buffer
* encoding: set by lavc
* decoding: unused
*/
char *stats_out; /* encoding statistics output buffer */
char *stats_in; /* encoding statistics input buffer (concatenated stuff from stats_out of pass1 should be placed here)*/
/**
* pass2 encoding statistics input buffer.
* concatenated stuff from stats_out of pass1 should be placed here
* encoding: allocated/set/freed by user
* decoding: unused
*/
char *stats_in;
/**
* ratecontrol qmin qmax limiting method
* 0-> clipping, 1-> use a nice continous function to limit qscale wthin qmin/qmax
* encoding: set by user.
* decoding: unused
*/
float rc_qsquish;
float rc_qmod_amp;
int rc_qmod_freq;
/**
* ratecontrol override, see RcOverride
* encoding: allocated/set/freed by user.
* decoding: unused
*/
RcOverride *rc_override;
int rc_override_count;
/**
* rate control equation
* encoding: set by user
* decoding: unused
*/
char *rc_eq;
/**
* maximum bitrate
* encoding: set by user.
* decoding: unused
*/
int rc_max_rate;
/**
* minimum bitrate
* encoding: set by user.
* decoding: unused
*/
int rc_min_rate;
/**
* decoder bitstream buffer size
* encoding: set by user.
* decoding: unused
*/
int rc_buffer_size;
float rc_buffer_aggressivity;
float i_quant_factor;/* qscale factor between i and p frames */
float i_quant_offset;/* qscale offset between i and p frames */
/**
* qscale factor between p and i frames
* encoding: set by user.
* decoding: unused
*/
float i_quant_factor;
/**
* qscale offset between p and i frames
* encoding: set by user.
* decoding: unused
*/
float i_quant_offset;
/**
* initial complexity for pass1 ratecontrol
* encoding: set by user.
* decoding: unused
*/
float rc_initial_cplx;
/**
* custom aspect ratio, used if aspect_info==FF_ASPECT_EXTENDED
* encoding: set by user.
* decoding: set by lavc.
*/
int aspected_width;
int aspected_height;
/**
* dct algorithm, see FF_DCT_* below
* encoding: set by user
* decoding: unused
*/
int dct_algo;
#define FF_DCT_AUTO 0
#define FF_DCT_FASTINT 1
@ -320,10 +621,13 @@ typedef struct AVCodecContext {
#define FF_DCT_MMX 3
#define FF_DCT_MLIB 4
long long int pts; /* timestamp in micro seconds
for decoding: the timestamp from the stream or 0
for encoding: the timestamp which will be stored in the stream
if 0 then the frame_rate will be used */
/**
* presentation timestamp in micro seconds (time when frame should be shown to user)
* if 0 then the frame_rate will be used as reference
* encoding: set by user
* decoding; set by lavc
*/
long long int pts;
//FIXME this should be reordered after kabis API is finished ...
//TODO kill kabi
@ -333,8 +637,11 @@ typedef struct AVCodecContext {
If you'll perform some changes then borrow new space from these fields
(void * can be safety replaced with struct * ;)
P L E A S E ! ! !
IMPORTANT: Never change order of already declared fields!!!
*/
Note: use avcodec_alloc_context instead of malloc to allocate this,
otherwise the ABI compatibility will be broken between versions
IMPORTANT: Never change order of already declared fields!!!
*/
//TODO: remove mess below
unsigned long long int
ull_res0,ull_res1,ull_res2,ull_res3,ull_res4,ull_res5,
ull_res6,ull_res7,ull_res8,ull_res9,ull_res10,ull_res11;

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