gif.c File Reference

#include "libavutil/opt.h"
#include "libavutil/imgutils.h"
#include "avcodec.h"
#include "bytestream.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
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 44 of file gif.c.

OFFSET

#define OFFSET

(

x

)

offsetof(GIFContext, x)

Definition at line 536 of file gif.c.

FLAGS

#define FLAGS   AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM

Definition at line 537 of file gif.c.

Enumeration Type Documentation

anonymous enum

anonymous enum

Enumerator
GF_OFFSETTING
GF_TRANSDIFF

Definition at line 62 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 67 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 90 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 99 of file gif.c.

get_palette_transparency_index()

static int get_palette_transparency_index ( const uint32_t *  palette )

static

Definition at line 120 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 138 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 154 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 233 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 292 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 451 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 475 of file gif.c.

gif_encode_close()

static int gif_encode_close ( AVCodecContext *  avctx )

static

Definition at line 523 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 538 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 547 of file gif.c.

ff_gif_encoder

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_CLEANUP,
}

Definition at line 554 of file gif.c.