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

Go to the source code of this file.

Data Structures

struct  GIFContext
 

Macros

#define BITSTREAM_WRITER_LE
 
#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 AVCodec 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

◆ BITSTREAM_WRITER_LE

#define BITSTREAM_WRITER_LE

Definition at line 33 of file gif.c.

◆ DEFAULT_TRANSPARENCY_INDEX

#define DEFAULT_TRANSPARENCY_INDEX   0x1f

Definition at line 45 of file gif.c.

◆ OFFSET

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

Definition at line 537 of file gif.c.

◆ FLAGS

#define FLAGS   AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM

Definition at line 538 of file gif.c.

Enumeration Type Documentation

◆ anonymous enum

anonymous enum
Enumerator
GF_OFFSETTING 
GF_TRANSDIFF 

Definition at line 63 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 68 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 91 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 100 of file gif.c.

◆ get_palette_transparency_index()

static int get_palette_transparency_index ( const uint32_t *  palette)
static

Definition at line 121 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 139 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 155 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 234 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 293 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 452 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 476 of file gif.c.

◆ gif_encode_close()

static int gif_encode_close ( AVCodecContext *  avctx)
static

Definition at line 524 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, "flags" },
{ "offsetting", "enable picture offsetting", 0, AV_OPT_TYPE_CONST, {.i64=GF_OFFSETTING}, INT_MIN, INT_MAX, FLAGS, "flags" },
{ "transdiff", "enable transparency detection between frames", 0, AV_OPT_TYPE_CONST, {.i64=GF_TRANSDIFF}, INT_MIN, INT_MAX, FLAGS, "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 539 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 548 of file gif.c.

◆ ff_gif_encoder

const AVCodec ff_gif_encoder
Initial value:
= {
.name = "gif",
.long_name = NULL_IF_CONFIG_SMALL("GIF (Graphics Interchange Format)"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_GIF,
.priv_data_size = sizeof(GIFContext),
.init = gif_encode_init,
.encode2 = gif_encode_frame,
.close = gif_encode_close,
.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
},
.priv_class = &gif_class,
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
}

Definition at line 555 of file gif.c.

FF_CODEC_CAP_INIT_THREADSAFE
#define FF_CODEC_CAP_INIT_THREADSAFE
The codec does not modify any global variables in the init function, allowing to call the init functi...
Definition: internal.h:42
AVPixelFormat
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
FLAGS
#define FLAGS
Definition: gif.c:538
gif_encode_close
static int gif_encode_close(AVCodecContext *avctx)
Definition: gif.c:524
init
static int init
Definition: av_tx.c:47
AV_PIX_FMT_BGR8
@ AV_PIX_FMT_BGR8
packed RGB 3:3:2, 8bpp, (msb)2B 3G 3R(lsb)
Definition: pixfmt.h:83
pix_fmts
static enum AVPixelFormat pix_fmts[]
Definition: libkvazaar.c:296
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:64
av_default_item_name
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
AV_PIX_FMT_RGB8
@ AV_PIX_FMT_RGB8
packed RGB 3:3:2, 8bpp, (msb)2R 3G 3B(lsb)
Definition: pixfmt.h:86
AV_PIX_FMT_GRAY8
@ AV_PIX_FMT_GRAY8
Y , 8bpp.
Definition: pixfmt.h:74
GF_TRANSDIFF
@ GF_TRANSDIFF
Definition: gif.c:65
AV_PIX_FMT_BGR4_BYTE
@ AV_PIX_FMT_BGR4_BYTE
packed RGB 1:2:1, 8bpp, (msb)1B 2G 1R(lsb)
Definition: pixfmt.h:85
OFFSET
#define OFFSET(x)
Definition: gif.c:537
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
gif_encode_init
static av_cold int gif_encode_init(AVCodecContext *avctx)
Definition: gif.c:452
GIFContext
Definition: gif.c:47
AV_CODEC_ID_GIF
@ AV_CODEC_ID_GIF
Definition: codec_id.h:147
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: internal.h:50
gif_class
static const AVClass gif_class
Definition: gif.c:548
AV_PIX_FMT_RGB4_BYTE
@ AV_PIX_FMT_RGB4_BYTE
packed RGB 1:2:1, 8bpp, (msb)1R 2G 1B(lsb)
Definition: pixfmt.h:88
AV_PIX_FMT_PAL8
@ AV_PIX_FMT_PAL8
8 bits with AV_PIX_FMT_RGB32 palette
Definition: pixfmt.h:77
gif_options
static const AVOption gif_options[]
Definition: gif.c:539
AV_PIX_FMT_NONE
@ AV_PIX_FMT_NONE
Definition: pixfmt.h:65
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AV_OPT_TYPE_BOOL
@ AV_OPT_TYPE_BOOL
Definition: opt.h:241
AV_OPT_TYPE_FLAGS
@ AV_OPT_TYPE_FLAGS
Definition: opt.h:223
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
gif_encode_frame
static int gif_encode_frame(AVCodecContext *avctx, AVPacket *pkt, const AVFrame *pict, int *got_packet)
Definition: gif.c:476
AV_OPT_TYPE_CONST
@ AV_OPT_TYPE_CONST
Definition: opt.h:233
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