webp_anim_dec.c File Reference

Animated WebP demuxer. More...

#include "avio_internal.h"
#include "demux.h"
#include "avformat.h"
#include "internal.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/mem.h"
#include "libavutil/opt.h"

Go to the source code of this file.

Data Structures
struct	WebPAnimDemuxContext

Macros
#define	VP8X_FLAG_ANIMATION   0x02
#define	VP8X_FLAG_XMP_METADATA   0x04
#define	VP8X_FLAG_EXIF_METADATA   0x08
#define	VP8X_FLAG_ALPHA   0x10
#define	VP8X_FLAG_ICC   0x20
#define	WEBP_DEFAULT_DELAY   100
	Major web browsers display WebPs at ~10-15fps when rate is not explicitly set or have too low values.
#define	WEBP_MIN_DELAY   10
	By default delay values less than this threshold considered to be invalid.

Functions
static int	webp_anim_probe (const AVProbeData *p)
static int	webp_anim_read_header (AVFormatContext *s)
static int	webp_anim_read_packet (AVFormatContext *s, AVPacket *pkt)

Variables
static const AVOption	options []
static const AVClass	demuxer_class
const FFInputFormat	ff_webp_anim_demuxer

Detailed Description

Animated WebP demuxer.

Definition in file webp_anim_dec.c.

Macro Definition Documentation

VP8X_FLAG_ANIMATION

#define VP8X_FLAG_ANIMATION   0x02

Definition at line 36 of file webp_anim_dec.c.

VP8X_FLAG_XMP_METADATA

#define VP8X_FLAG_XMP_METADATA   0x04

Definition at line 37 of file webp_anim_dec.c.

VP8X_FLAG_EXIF_METADATA

#define VP8X_FLAG_EXIF_METADATA   0x08

Definition at line 38 of file webp_anim_dec.c.

VP8X_FLAG_ALPHA

#define VP8X_FLAG_ALPHA   0x10

Definition at line 39 of file webp_anim_dec.c.

VP8X_FLAG_ICC

#define VP8X_FLAG_ICC   0x20

Definition at line 40 of file webp_anim_dec.c.

WEBP_DEFAULT_DELAY

#define WEBP_DEFAULT_DELAY   100

Major web browsers display WebPs at ~10-15fps when rate is not explicitly set or have too low values.

We assume default rate to be 10. Default delay = 1000 microseconds / 10fps = 100 milliseconds per frame.

Definition at line 82 of file webp_anim_dec.c.

WEBP_MIN_DELAY

#define WEBP_MIN_DELAY   10

By default delay values less than this threshold considered to be invalid.

Definition at line 86 of file webp_anim_dec.c.

Function Documentation

webp_anim_probe()

static int webp_anim_probe ( const AVProbeData * p )

static

Definition at line 88 of file webp_anim_dec.c.

webp_anim_read_header()

static int webp_anim_read_header ( AVFormatContext * s )

static

Definition at line 102 of file webp_anim_dec.c.

webp_anim_read_packet()

static int webp_anim_read_packet ( AVFormatContext * s, AVPacket * pkt )

static

Definition at line 236 of file webp_anim_dec.c.

Variable Documentation

options

const AVOption options[]

static

Initial value:

= {
    { "min_delay",      "minimum valid delay between frames (in milliseconds)",  0x42 ,     AV_OPT_TYPE_INT,  {.i64 = WEBP_MIN_DELAY},     0, 1000 * 60, AV_OPT_FLAG_DECODING_PARAM },
    { "max_webp_delay", "maximum valid delay between frames (in milliseconds)",  0x42 ,     AV_OPT_TYPE_INT,  {.i64 = 0xffffff},           0, 0xffffff,  AV_OPT_FLAG_DECODING_PARAM },
    { "default_delay",  "default delay between frames (in milliseconds)",        0x42 , AV_OPT_TYPE_INT,  {.i64 = WEBP_DEFAULT_DELAY}, 0, 1000 * 60, AV_OPT_FLAG_DECODING_PARAM },
    { "ignore_loop",    "ignore loop setting",                                   0x42 ,   AV_OPT_TYPE_BOOL, {.i64 = 1},                  0, 1,         AV_OPT_FLAG_DECODING_PARAM },
    { "usebgcolor",     "use background color from ANIM chunk",                  0x42 ,    AV_OPT_TYPE_BOOL, {.i64 = 0},                  0, 1,         AV_OPT_FLAG_DECODING_PARAM },
    { NULL },
}

Definition at line 349 of file webp_anim_dec.c.

demuxer_class

const AVClass demuxer_class

static

Initial value:

= {
    .class_name = "Animated WebP demuxer",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
    .category   = AV_CLASS_CATEGORY_DEMUXER,
}

Definition at line 358 of file webp_anim_dec.c.

ff_webp_anim_demuxer

const FFInputFormat ff_webp_anim_demuxer

Initial value:

= {
    .p.name         = "webp_anim",
    .p.long_name    = NULL_IF_CONFIG_SMALL("Animated WebP"),
    .p.flags        = AVFMT_GENERIC_INDEX,
    .p.priv_class   = &demuxer_class,
    .priv_data_size = sizeof(WebPAnimDemuxContext),
    .read_probe     = webp_anim_probe,
    .read_header    = webp_anim_read_header,
    .read_packet    = webp_anim_read_packet,
}

Definition at line 366 of file webp_anim_dec.c.