FFmpeg
Data Structures | Macros | Enumerations | Functions | Variables
gif.c File Reference
#include "libavutil/opt.h"
#include "avcodec.h"
#include "bytestream.h"
#include "codec_internal.h"
#include "encode.h"
#include "lzw.h"
#include "gif.h"

Go to the source code of this file.

Data Structures

struct  GIFContext
 

Macros

#define DEFAULT_TRANSPARENCY_INDEX   0x1f
 
#define OFFSET(x)   offsetof(GIFContext, x)
 
#define FLAGS   AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
 

Enumerations

enum  { GF_OFFSETTING = 1<<0, GF_TRANSDIFF = 1<<1 }
 

Functions

static void shrink_palette (const uint32_t *src, uint8_t *map, uint32_t *dst, size_t *palette_count)
 
static void remap_frame_to_palette (const uint8_t *src, int src_linesize, uint8_t *dst, int dst_linesize, int w, int h, uint8_t *map)
 
static int is_image_translucent (AVCodecContext *avctx, const uint8_t *buf, const int linesize)
 
static int get_palette_transparency_index (const uint32_t *palette)
 
static int pick_palette_entry (const uint8_t *buf, int linesize, int w, int h)
 
static void gif_crop_translucent (AVCodecContext *avctx, const uint8_t *buf, const int linesize, int *width, int *height, int *x_start, int *y_start)
 
static void gif_crop_opaque (AVCodecContext *avctx, const uint32_t *palette, const uint8_t *buf, const int linesize, int *width, int *height, int *x_start, int *y_start)
 
static int gif_image_write_image (AVCodecContext *avctx, uint8_t **bytestream, uint8_t *end, const uint32_t *palette, const uint8_t *buf, const int linesize, AVPacket *pkt)
 
static av_cold int gif_encode_init (AVCodecContext *avctx)
 
static int gif_encode_frame (AVCodecContext *avctx, AVPacket *pkt, const AVFrame *pict, int *got_packet)
 
static int gif_encode_close (AVCodecContext *avctx)
 

Variables

static const AVOption gif_options []
 
static const AVClass gif_class
 
const FFCodec ff_gif_encoder
 

Detailed Description

GIF encoder

See also
http://www.w3.org/Graphics/GIF/spec-gif89a.txt

Definition in file gif.c.

Macro Definition Documentation

◆ DEFAULT_TRANSPARENCY_INDEX

#define DEFAULT_TRANSPARENCY_INDEX   0x1f

Definition at line 41 of file gif.c.

◆ OFFSET

#define OFFSET (   x)    offsetof(GIFContext, x)

Definition at line 532 of file gif.c.

◆ FLAGS

#define FLAGS   AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM

Definition at line 533 of file gif.c.

Enumeration Type Documentation

◆ anonymous enum

anonymous enum
Enumerator
GF_OFFSETTING 
GF_TRANSDIFF 

Definition at line 59 of file gif.c.

Function Documentation

◆ shrink_palette()

static void shrink_palette ( const uint32_t *  src,
uint8_t *  map,
uint32_t *  dst,
size_t *  palette_count 
)
static

Definition at line 64 of file gif.c.

◆ remap_frame_to_palette()

static void remap_frame_to_palette ( const uint8_t *  src,
int  src_linesize,
uint8_t *  dst,
int  dst_linesize,
int  w,
int  h,
uint8_t *  map 
)
static

Definition at line 87 of file gif.c.

◆ is_image_translucent()

static int is_image_translucent ( AVCodecContext *  avctx,
const uint8_t *  buf,
const int  linesize 
)
static

Definition at line 96 of file gif.c.

◆ get_palette_transparency_index()

static int get_palette_transparency_index ( const uint32_t *  palette)
static

Definition at line 117 of file gif.c.

Referenced by gif_encode_frame().

◆ pick_palette_entry()

static int pick_palette_entry ( const uint8_t *  buf,
int  linesize,
int  w,
int  h 
)
static

Definition at line 135 of file gif.c.

◆ gif_crop_translucent()

static void gif_crop_translucent ( AVCodecContext *  avctx,
const uint8_t *  buf,
const int  linesize,
int *  width,
int *  height,
int *  x_start,
int *  y_start 
)
static

Definition at line 151 of file gif.c.

◆ gif_crop_opaque()

static void gif_crop_opaque ( AVCodecContext *  avctx,
const uint32_t *  palette,
const uint8_t *  buf,
const int  linesize,
int *  width,
int *  height,
int *  x_start,
int *  y_start 
)
static

Definition at line 230 of file gif.c.

◆ gif_image_write_image()

static int gif_image_write_image ( AVCodecContext *  avctx,
uint8_t **  bytestream,
uint8_t *  end,
const uint32_t *  palette,
const uint8_t *  buf,
const int  linesize,
AVPacket *  pkt 
)
static

Definition at line 289 of file gif.c.

Referenced by gif_encode_frame().

◆ gif_encode_init()

static av_cold int gif_encode_init ( AVCodecContext *  avctx)
static

Definition at line 448 of file gif.c.

◆ gif_encode_frame()

static int gif_encode_frame ( AVCodecContext *  avctx,
AVPacket *  pkt,
const AVFrame *  pict,
int *  got_packet 
)
static

Definition at line 472 of file gif.c.

◆ gif_encode_close()

static int gif_encode_close ( AVCodecContext *  avctx)
static

Definition at line 519 of file gif.c.

Variable Documentation

◆ gif_options

const AVOption gif_options[]
static
Initial value:
= {
{ "gifflags", "set GIF flags", OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = GF_OFFSETTING|GF_TRANSDIFF}, 0, INT_MAX, FLAGS, .unit = "flags" },
{ "offsetting", "enable picture offsetting", 0, AV_OPT_TYPE_CONST, {.i64=GF_OFFSETTING}, INT_MIN, INT_MAX, FLAGS, .unit = "flags" },
{ "transdiff", "enable transparency detection between frames", 0, AV_OPT_TYPE_CONST, {.i64=GF_TRANSDIFF}, INT_MIN, INT_MAX, FLAGS, .unit = "flags" },
{ "gifimage", "enable encoding only images per frame", OFFSET(image), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, FLAGS },
{ "global_palette", "write a palette to the global gif header where feasible", OFFSET(use_global_palette), AV_OPT_TYPE_BOOL, {.i64=1}, 0, 1, FLAGS },
{ NULL }
}

Definition at line 534 of file gif.c.

◆ gif_class

const AVClass gif_class
static
Initial value:
= {
.class_name = "GIF encoder",
.item_name = av_default_item_name,
.option = gif_options,
.version = LIBAVUTIL_VERSION_INT,
}

Definition at line 543 of file gif.c.

◆ ff_gif_encoder

const FFCodec ff_gif_encoder
Initial value:
= {
.p.name = "gif",
CODEC_LONG_NAME("GIF (Graphics Interchange Format)"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_GIF,
.p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,
.priv_data_size = sizeof(GIFContext),
.init = gif_encode_init,
FF_CODEC_ENCODE_CB(gif_encode_frame),
.close = gif_encode_close,
.p.pix_fmts = (const enum AVPixelFormat[]){
AV_PIX_FMT_RGB8, AV_PIX_FMT_BGR8, AV_PIX_FMT_RGB4_BYTE, AV_PIX_FMT_BGR4_BYTE,
AV_PIX_FMT_GRAY8, AV_PIX_FMT_PAL8, AV_PIX_FMT_NONE
},
.p.priv_class = &gif_class,
.caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
}

Definition at line 550 of file gif.c.

AVPixelFormat
AVPixelFormat
Pixel format.
Definition: pixfmt.h:71
FF_CODEC_CAP_INIT_CLEANUP
#define FF_CODEC_CAP_INIT_CLEANUP
The codec allows calling the close function for deallocation even if the init function returned a fai...
Definition: codec_internal.h:42
FLAGS
#define FLAGS
Definition: gif.c:533
gif_encode_close
static int gif_encode_close(AVCodecContext *avctx)
Definition: gif.c:519
FF_CODEC_ENCODE_CB
#define FF_CODEC_ENCODE_CB(func)
Definition: codec_internal.h:296
AV_PIX_FMT_BGR8
@ AV_PIX_FMT_BGR8
packed RGB 3:3:2, 8bpp, (msb)2B 3G 3R(lsb)
Definition: pixfmt.h:90
GF_TRANSDIFF
@ GF_TRANSDIFF
Definition: gif.c:61
AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE
#define AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE
This encoder can reorder user opaque values from input AVFrames and return them with corresponding ou...
Definition: codec.h:159
CODEC_LONG_NAME
#define CODEC_LONG_NAME(str)
Definition: codec_internal.h:272
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
NULL
#define NULL
Definition: coverity.c:32
GF_OFFSETTING
@ GF_OFFSETTING
Definition: gif.c:60
av_default_item_name
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:237
AV_PIX_FMT_RGB8
@ AV_PIX_FMT_RGB8
packed RGB 3:3:2, 8bpp, (msb)3R 3G 2B(lsb)
Definition: pixfmt.h:93
AV_PIX_FMT_GRAY8
@ AV_PIX_FMT_GRAY8
Y , 8bpp.
Definition: pixfmt.h:81
AV_PIX_FMT_BGR4_BYTE
@ AV_PIX_FMT_BGR4_BYTE
packed RGB 1:2:1, 8bpp, (msb)1B 2G 1R(lsb)
Definition: pixfmt.h:92
OFFSET
#define OFFSET(x)
Definition: gif.c:532
init
int(* init)(AVBSFContext *ctx)
Definition: dts2pts.c:365
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
gif_encode_init
static av_cold int gif_encode_init(AVCodecContext *avctx)
Definition: gif.c:448
GIFContext
Definition: gif.c:43
AV_CODEC_ID_GIF
@ AV_CODEC_ID_GIF
Definition: codec_id.h:149
gif_class
static const AVClass gif_class
Definition: gif.c:543
AV_PIX_FMT_RGB4_BYTE
@ AV_PIX_FMT_RGB4_BYTE
packed RGB 1:2:1, 8bpp, (msb)1R 2G 1B(lsb)
Definition: pixfmt.h:95
AV_PIX_FMT_PAL8
@ AV_PIX_FMT_PAL8
8 bits with AV_PIX_FMT_RGB32 palette
Definition: pixfmt.h:84
gif_options
static const AVOption gif_options[]
Definition: gif.c:534
AV_PIX_FMT_NONE
@ AV_PIX_FMT_NONE
Definition: pixfmt.h:72
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AV_OPT_TYPE_BOOL
@ AV_OPT_TYPE_BOOL
Definition: opt.h:251
AV_OPT_TYPE_FLAGS
@ AV_OPT_TYPE_FLAGS
Definition: opt.h:234
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:482
gif_encode_frame
static int gif_encode_frame(AVCodecContext *avctx, AVPacket *pkt, const AVFrame *pict, int *got_packet)
Definition: gif.c:472
AV_OPT_TYPE_CONST
@ AV_OPT_TYPE_CONST
Definition: opt.h:244
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