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change gif demuxer to gif decoder

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Originally committed as revision 6760 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Baptiste Coudurier 2006-10-22 15:05:03 +00:00
parent b92f5a6b31
commit 06d392a7cc
7 changed files with 555 additions and 2 deletions
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1
Changelog
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@ -64,6 +64,7 @@ version <next>
- Tiertex .seq demuxer/video decoder
- MTV demuxer
- TIFF picture decoder
- GIF picture decoder
version 0.4.9-pre1:

1
MAINTAINERS
View File

@ -121,6 +121,7 @@ Codecs:
flashsv.c Benjamin Larsson
flicvideo.c Mike Melanson
g726.c Roman Shaposhnik
gifdec.c Baptiste Coudurier
h264* Loren Merritt, Michael Niedermayer
h261* Michael Niedermayer
h263* Michael Niedermayer

1
libavcodec/Makefile
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@ -84,6 +84,7 @@ OBJS-$(CONFIG_FLASHSV_DECODER) += flashsv.o
OBJS-$(CONFIG_FLIC_DECODER) += flicvideo.o
OBJS-$(CONFIG_FOURXM_DECODER) += 4xm.o
OBJS-$(CONFIG_FRAPS_DECODER) += fraps.o
OBJS-$(CONFIG_GIF_DECODER) += gifdec.o
OBJS-$(CONFIG_H261_DECODER) += h261.o
OBJS-$(CONFIG_H261_ENCODER) += h261.o
OBJS-$(CONFIG_H264_DECODER) += h264.o

3
libavcodec/allcodecs.c
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@ -193,6 +193,9 @@ void avcodec_register_all(void)
#endif //CONFIG_RAWVIDEO_ENCODER
/* decoders */
#ifdef CONFIG_GIF_DECODER
register_avcodec(&gif_decoder);
#endif
#ifdef CONFIG_H263_DECODER
register_avcodec(&h263_decoder);
#endif //CONFIG_H263_DECODER

6
libavcodec/avcodec.h
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@ -37,8 +37,8 @@ extern "C" {
#define AV_STRINGIFY(s) AV_TOSTRING(s)
#define AV_TOSTRING(s) #s
#define LIBAVCODEC_VERSION_INT ((51<<16)+(20<<8)+0)
#define LIBAVCODEC_VERSION 51.20.0
#define LIBAVCODEC_VERSION_INT ((51<<16)+(21<<8)+0)
#define LIBAVCODEC_VERSION 51.21.0
#define LIBAVCODEC_BUILD LIBAVCODEC_VERSION_INT
#define LIBAVCODEC_IDENT "Lavc" AV_STRINGIFY(LIBAVCODEC_VERSION)
@ -148,6 +148,7 @@ enum CodecID {
CODEC_ID_DSICINVIDEO,
CODEC_ID_TIERTEXSEQVIDEO,
CODEC_ID_TIFF,
CODEC_ID_GIF,
/* various pcm "codecs" */
CODEC_ID_PCM_S16LE= 0x10000,
@ -2177,6 +2178,7 @@ extern AVCodec sonic_ls_encoder;
extern AVCodec svq1_encoder;
extern AVCodec x264_encoder;
extern AVCodec gif_decoder;
extern AVCodec h263_decoder;
extern AVCodec h261_decoder;
extern AVCodec mpeg4_decoder;

50
libavcodec/bytestream.h Normal file
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@ -0,0 +1,50 @@
/*
* Bytestream functions
* copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@free.fr>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef FFMPEG_BYTESTREAM_H
#define FFMPEG_BYTESTREAM_H
static always_inline unsigned int bytestream_get_le32(uint8_t **b)
{
(*b) += 4;
return LE_32(*b - 4);
}
static always_inline unsigned int bytestream_get_le16(uint8_t **b)
{
(*b) += 2;
return LE_16(*b - 2);
}
static always_inline unsigned int bytestream_get_byte(uint8_t **b)
{
(*b)++;
return (*b)[-1];
}
static always_inline unsigned int bytestream_get_buffer(uint8_t **b, uint8_t *dst, unsigned int size)
{
memcpy(dst, *b, size);
(*b) += size;
return size;
}
#endif /* FFMPEG_BYTESTREAM_H */

495
libavcodec/gifdec.c Normal file
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@ -0,0 +1,495 @@
/*
* GIF decoder
* Copyright (c) 2003 Fabrice Bellard.
* Copyright (c) 2006 Baptiste Coudurier.
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
//#define DEBUG
#include "avcodec.h"
#include "bytestream.h"
#define MAXBITS 12
#define SIZTABLE (1<<MAXBITS)
#define GCE_DISPOSAL_NONE 0
#define GCE_DISPOSAL_INPLACE 1
#define GCE_DISPOSAL_BACKGROUND 2
#define GCE_DISPOSAL_RESTORE 3
typedef struct GifState {
int screen_width;
int screen_height;
int bits_per_pixel;
int background_color_index;
int transparent_color_index;
int color_resolution;
uint8_t *image_buf;
int image_linesize;
uint32_t image_palette[256];
int pix_fmt;
/* after the frame is displayed, the disposal method is used */
int gce_disposal;
/* delay during which the frame is shown */
int gce_delay;
/* LZW compatible decoder */
uint8_t *bytestream;
int eob_reached;
uint8_t *pbuf, *ebuf;
int bbits;
unsigned int bbuf;
int cursize; /* The current code size */
int curmask;
int codesize;
int clear_code;
int end_code;
int newcodes; /* First available code */
int top_slot; /* Highest code for current size */
int slot; /* Last read code */
int fc, oc;
uint8_t *sp;
uint8_t stack[SIZTABLE];
uint8_t suffix[SIZTABLE];
uint16_t prefix[SIZTABLE];
/* aux buffers */
uint8_t global_palette[256 * 3];
uint8_t local_palette[256 * 3];
uint8_t buf[256];
} GifState;
static const uint8_t gif87a_sig[6] = "GIF87a";
static const uint8_t gif89a_sig[6] = "GIF89a";
static const uint16_t mask[17] =
{
0x0000, 0x0001, 0x0003, 0x0007,
0x000F, 0x001F, 0x003F, 0x007F,
0x00FF, 0x01FF, 0x03FF, 0x07FF,
0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF
};
static void GLZWDecodeInit(GifState * s, int csize)
{
/* read buffer */
s->eob_reached = 0;
s->pbuf = s->buf;
s->ebuf = s->buf;
s->bbuf = 0;
s->bbits = 0;
/* decoder */
s->codesize = csize;
s->cursize = s->codesize + 1;
s->curmask = mask[s->cursize];
s->top_slot = 1 << s->cursize;
s->clear_code = 1 << s->codesize;
s->end_code = s->clear_code + 1;
s->slot = s->newcodes = s->clear_code + 2;
s->oc = s->fc = 0;
s->sp = s->stack;
}
/* XXX: optimize */
static inline int GetCode(GifState * s)
{
int c, sizbuf;
uint8_t *ptr;
while (s->bbits < s->cursize) {
ptr = s->pbuf;
if (ptr >= s->ebuf) {
if (!s->eob_reached) {
sizbuf = bytestream_get_byte(&s->bytestream);
s->ebuf = s->buf + sizbuf;
s->pbuf = s->buf;
if (sizbuf > 0) {
bytestream_get_buffer(&s->bytestream, s->buf, sizbuf);
} else {
s->eob_reached = 1;
}
}
ptr = s->pbuf;
}
s->bbuf |= ptr[0] << s->bbits;
ptr++;
s->pbuf = ptr;
s->bbits += 8;
}
c = s->bbuf & s->curmask;
s->bbuf >>= s->cursize;
s->bbits -= s->cursize;
return c;
}
/* NOTE: the algorithm here is inspired from the LZW GIF decoder
written by Steven A. Bennett in 1987. */
/* return the number of byte decoded */
static int GLZWDecode(GifState * s, uint8_t * buf, int len)
{
int l, c, code, oc, fc;
uint8_t *sp;
if (s->end_code < 0)
return 0;
l = len;
sp = s->sp;
oc = s->oc;
fc = s->fc;
while (sp > s->stack) {
*buf++ = *(--sp);
if ((--l) == 0)
goto the_end;
}
for (;;) {
c = GetCode(s);
if (c == s->end_code) {
s->end_code = -1;
break;
} else if (c == s->clear_code) {
s->cursize = s->codesize + 1;
s->curmask = mask[s->cursize];
s->slot = s->newcodes;
s->top_slot = 1 << s->cursize;
while ((c = GetCode(s)) == s->clear_code);
if (c == s->end_code) {
s->end_code = -1;
break;
}
/* test error */
if (c >= s->slot)
c = 0;
fc = oc = c;
*buf++ = c;
if ((--l) == 0)
break;
} else {
code = c;
if (code >= s->slot) {
*sp++ = fc;
code = oc;
}
while (code >= s->newcodes) {
*sp++ = s->suffix[code];
code = s->prefix[code];
}
*sp++ = code;
if (s->slot < s->top_slot) {
s->suffix[s->slot] = fc = code;
s->prefix[s->slot++] = oc;
oc = c;
}
if (s->slot >= s->top_slot) {
if (s->cursize < MAXBITS) {
s->top_slot <<= 1;
s->curmask = mask[++s->cursize];
}
}
while (sp > s->stack) {
*buf++ = *(--sp);
if ((--l) == 0)
goto the_end;
}
}
}
the_end:
s->sp = sp;
s->oc = oc;
s->fc = fc;
return len - l;
}
static int gif_read_image(GifState *s)
{
int left, top, width, height, bits_per_pixel, code_size, flags;
int is_interleaved, has_local_palette, y, x, pass, y1, linesize, n, i;
uint8_t *ptr, *line, *d, *spal, *palette, *sptr, *ptr1;
left = bytestream_get_le16(&s->bytestream);
top = bytestream_get_le16(&s->bytestream);
width = bytestream_get_le16(&s->bytestream);
height = bytestream_get_le16(&s->bytestream);
flags = bytestream_get_byte(&s->bytestream);
is_interleaved = flags & 0x40;
has_local_palette = flags & 0x80;
bits_per_pixel = (flags & 0x07) + 1;
#ifdef DEBUG
printf("gif: image x=%d y=%d w=%d h=%d\n", left, top, width, height);
#endif
if (has_local_palette) {
bytestream_get_buffer(&s->bytestream, s->local_palette, 3 * (1 << bits_per_pixel));
palette = s->local_palette;
} else {
palette = s->global_palette;
bits_per_pixel = s->bits_per_pixel;
}
/* verify that all the image is inside the screen dimensions */
if (left + width > s->screen_width ||
top + height > s->screen_height)
return -EINVAL;
/* build the palette */
n = (1 << bits_per_pixel);
spal = palette;
for(i = 0; i < n; i++) {
s->image_palette[i] = (0xff << 24) |
(spal[0] << 16) | (spal[1] << 8) | (spal[2]);
spal += 3;
}
for(; i < 256; i++)
s->image_palette[i] = (0xff << 24);
/* handle transparency */
if (s->transparent_color_index >= 0)
s->image_palette[s->transparent_color_index] = 0;
line = NULL;
/* now get the image data */
code_size = bytestream_get_byte(&s->bytestream);
GLZWDecodeInit(s, code_size);
/* read all the image */
linesize = s->image_linesize;
ptr1 = s->image_buf + top * linesize + (left * 3);
ptr = ptr1;
pass = 0;
y1 = 0;
for (y = 0; y < height; y++) {
GLZWDecode(s, ptr, width);
if (is_interleaved) {
switch(pass) {
default:
case 0:
case 1:
y1 += 8;
ptr += linesize * 8;
if (y1 >= height) {
y1 = 4;
if (pass == 0)
ptr = ptr1 + linesize * 4;
else
ptr = ptr1 + linesize * 2;
pass++;
}
break;
case 2:
y1 += 4;
ptr += linesize * 4;
if (y1 >= height) {
y1 = 1;
ptr = ptr1 + linesize;
pass++;
}
break;
case 3:
y1 += 2;
ptr += linesize * 2;
break;
}
} else {
ptr += linesize;
}
}
av_free(line);
/* read the garbage data until end marker is found */
while (!s->eob_reached)
GetCode(s);
return 0;
}
static int gif_read_extension(GifState *s)
{
int ext_code, ext_len, i, gce_flags, gce_transparent_index;
/* extension */
ext_code = bytestream_get_byte(&s->bytestream);
ext_len = bytestream_get_byte(&s->bytestream);
#ifdef DEBUG
printf("gif: ext_code=0x%x len=%d\n", ext_code, ext_len);
#endif
switch(ext_code) {
case 0xf9:
if (ext_len != 4)
goto discard_ext;
s->transparent_color_index = -1;
gce_flags = bytestream_get_byte(&s->bytestream);
s->gce_delay = bytestream_get_le16(&s->bytestream);
gce_transparent_index = bytestream_get_byte(&s->bytestream);
if (gce_flags & 0x01)
s->transparent_color_index = gce_transparent_index;
else
s->transparent_color_index = -1;
s->gce_disposal = (gce_flags >> 2) & 0x7;
#ifdef DEBUG
printf("gif: gce_flags=%x delay=%d tcolor=%d disposal=%d\n",
gce_flags, s->gce_delay,
s->transparent_color_index, s->gce_disposal);
#endif
ext_len = bytestream_get_byte(&s->bytestream);
break;
}
/* NOTE: many extension blocks can come after */
discard_ext:
while (ext_len != 0) {
for (i = 0; i < ext_len; i++)
bytestream_get_byte(&s->bytestream);
ext_len = bytestream_get_byte(&s->bytestream);
#ifdef DEBUG
printf("gif: ext_len1=%d\n", ext_len);
#endif
}
return 0;
}
static int gif_read_header1(GifState *s)
{
uint8_t sig[6];
int ret, v, n;
int has_global_palette;
/* read gif signature */
bytestream_get_buffer(&s->bytestream, sig, 6);
if (memcmp(sig, gif87a_sig, 6) != 0 &&
memcmp(sig, gif89a_sig, 6) != 0)
return -1;
/* read screen header */
s->transparent_color_index = -1;
s->screen_width = bytestream_get_le16(&s->bytestream);
s->screen_height = bytestream_get_le16(&s->bytestream);
if( (unsigned)s->screen_width > 32767
|| (unsigned)s->screen_height > 32767){
av_log(NULL, AV_LOG_ERROR, "picture size too large\n");
return -1;
}
v = bytestream_get_byte(&s->bytestream);
s->color_resolution = ((v & 0x70) >> 4) + 1;
has_global_palette = (v & 0x80);
s->bits_per_pixel = (v & 0x07) + 1;
s->background_color_index = bytestream_get_byte(&s->bytestream);
bytestream_get_byte(&s->bytestream); /* ignored */
#ifdef DEBUG
printf("gif: screen_w=%d screen_h=%d bpp=%d global_palette=%d\n",
s->screen_width, s->screen_height, s->bits_per_pixel,
has_global_palette);
#endif
if (has_global_palette) {
n = 1 << s->bits_per_pixel;
bytestream_get_buffer(&s->bytestream, s->global_palette, n * 3);
}
return 0;
}
static int gif_parse_next_image(GifState *s)
{
int ret, code;
for (;;) {
code = bytestream_get_byte(&s->bytestream);
#ifdef DEBUG
printf("gif: code=%02x '%c'\n", code, code);
#endif
switch (code) {
case ',':
if (gif_read_image(s) < 0)
return -1;
ret = 0;
goto the_end;
case ';':
/* end of image */
ret = -1;
goto the_end;
case '!':
if (gif_read_extension(s) < 0)
return -1;
break;
case EOF:
default:
/* error or errneous EOF */
ret = -1;
goto the_end;
}
}
the_end:
return ret;
}
static int gif_decode_init(AVCodecContext *avctx)
{
GifState *s = avctx->priv_data;
return 0;
}
static int gif_decode_frame(AVCodecContext *avctx, void *data, int *data_size, uint8_t *buf, int buf_size)
{
GifState *s = avctx->priv_data;
AVFrame *picture = data;
int ret;
s->bytestream = buf;
if (gif_read_header1(s) < 0)
return -1;
/* allocate image buffer */
s->image_linesize = s->screen_width * 3;
s->image_buf = av_malloc(s->screen_height * s->image_linesize);
if (!s->image_buf)
return -ENOMEM;
s->pix_fmt = PIX_FMT_PAL8;
/* now we are ready: build format streams */
/* XXX: check if screen size is always valid */
avctx->width = s->screen_width;
avctx->height = s->screen_height;
avctx->pix_fmt = PIX_FMT_PAL8;
ret = gif_parse_next_image(s);
if (ret < 0)
return ret;
picture->data[0] = s->image_buf;
picture->linesize[0] = s->image_linesize;
picture->data[1] = s->image_palette;
picture->linesize[1] = 4;
*data_size = sizeof(AVPicture);
return 0;
}
AVCodec gif_decoder = {
"gif",
CODEC_TYPE_VIDEO,
CODEC_ID_GIF,
sizeof(GifState),
gif_decode_init,
NULL,
NULL,
gif_decode_frame,
};