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mpv/libmpdemux/demux_gif.c

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/*
GIF file parser for MPlayer
by Joey Parrish
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "config.h"
#include "mp_msg.h"
#include "help_mp.h"
#include "stream/stream.h"
#include "demuxer.h"
#include "stheader.h"
#include <gif_lib.h>
#include "libvo/fastmemcpy.h"
typedef struct {
int current_pts;
unsigned char *palette;
GifFileType *gif;
int w, h;
int useref;
uint8_t *refimg;
} gif_priv_t;
#define GIF_SIGNATURE (('G' << 16) | ('I' << 8) | 'F')
#ifndef HAVE_GIF_TVT_HACK
// not supported by certain versions of the library
int my_read_gif(GifFileType *gif, uint8_t *buf, int len) {
return stream_read(gif->UserData, buf, len);
}
#endif
static int gif_check_file(demuxer_t *demuxer)
{
if (stream_read_int24(demuxer->stream) == GIF_SIGNATURE)
return DEMUXER_TYPE_GIF;
return 0;
}
static void memcpy_transp_pic(uint8_t *dst, uint8_t *src, int w, int h,
int dstride, int sstride, int transp, uint8_t trans_col) {
if (transp) {
dstride -= w;
sstride -= w;
while (h-- > 0) {
int wleft = w;
while (wleft-- > 0) {
if (*src != trans_col)
*dst = *src;
dst++; src++;
}
dst += dstride;
src += sstride;
}
} else
memcpy_pic(dst, src, w, h, dstride, sstride);
}
static int demux_gif_fill_buffer(demuxer_t *demuxer, demux_stream_t *ds)
{
gif_priv_t *priv = demuxer->priv;
GifFileType *gif = priv->gif;
GifRecordType type = UNDEFINED_RECORD_TYPE;
int len = 0;
demux_packet_t *dp = NULL;
ColorMapObject *effective_map = NULL;
uint8_t *buf = NULL;
int refmode = 0;
int transparency = 0;
uint8_t transparent_col;
while (type != IMAGE_DESC_RECORD_TYPE) {
if (DGifGetRecordType(gif, &type) == GIF_ERROR) {
PrintGifError();
return 0; // oops
}
if (type == TERMINATE_RECORD_TYPE)
return 0; // eof
if (type == SCREEN_DESC_RECORD_TYPE) {
if (DGifGetScreenDesc(gif) == GIF_ERROR) {
PrintGifError();
return 0; // oops
}
}
if (type == EXTENSION_RECORD_TYPE) {
int code;
unsigned char *p = NULL;
if (DGifGetExtension(gif, &code, &p) == GIF_ERROR) {
PrintGifError();
return 0; // oops
}
if (code == 0xF9) {
int frametime = 0;
if (p[0] == 4) // is the length correct?
{
transparency = p[1] & 1;
refmode = (p[1] >> 2) & 3;
// HACK: specification says
// > 0 - No disposal specified. The decoder is not required to take any action.
// but browsers treat it the same way as
// > 1 - Do not dispose. The graphic is to be left in place.
// Some broken files rely on this, e.g.
// http://samples.mplayerhq.hu/GIF/broken-gif/CLAIRE.GIF
if (refmode == 0) refmode = 1;
frametime = (p[3] << 8) | p[2]; // set the time, centiseconds
transparent_col = p[4];
}
priv->current_pts += frametime;
} else if ((code == 0xFE) && (verbose)) { // comment extension
// print iff verbose
printf("GIF comment: ");
while (p != NULL) {
int length = p[0];
char *comments = p + 1;
comments[length] = 0;
printf("%s", comments);
if (DGifGetExtensionNext(gif, &p) == GIF_ERROR) {
PrintGifError();
return 0; // oops
}
}
printf("\n");
}
while (p != NULL) {
if (DGifGetExtensionNext(gif, &p) == GIF_ERROR) {
PrintGifError();
return 0; // oops
}
}
}
}
if (DGifGetImageDesc(gif) == GIF_ERROR) {
PrintGifError();
return 0; // oops
}
len = gif->Image.Width * gif->Image.Height;
dp = new_demux_packet(priv->w * priv->h);
buf = calloc(gif->Image.Width, gif->Image.Height);
if (priv->useref)
memcpy(dp->buffer, priv->refimg, priv->w * priv->h);
else
memset(dp->buffer, gif->SBackGroundColor, priv->w * priv->h);
if (DGifGetLine(gif, buf, len) == GIF_ERROR) {
PrintGifError();
return 0; // oops
}
effective_map = gif->Image.ColorMap;
if (effective_map == NULL) effective_map = gif->SColorMap;
{
int y;
int cnt = FFMIN(effective_map->ColorCount, 256);
int l = av_clip(gif->Image.Left, 0, priv->w);
int t = av_clip(gif->Image.Top, 0, priv->h);
int w = av_clip(gif->Image.Width, 0, priv->w - l);
int h = av_clip(gif->Image.Height, 0, priv->h - t);
unsigned char *dest = dp->buffer + priv->w * t + l;
// copy the palette
for (y = 0; y < cnt; y++) {
priv->palette[(y * 4) + 0] = effective_map->Colors[y].Blue;
priv->palette[(y * 4) + 1] = effective_map->Colors[y].Green;
priv->palette[(y * 4) + 2] = effective_map->Colors[y].Red;
priv->palette[(y * 4) + 3] = 0;
}
if (gif->Image.Interlace) {
uint8_t *s = buf;
int ih = (h - 0 + 7) >> 3;
memcpy_transp_pic(dest, s, w, ih,
priv->w << 3, gif->Image.Width,
transparency, transparent_col);
s += ih * w;
ih = (h - 4 + 7) >> 3;
memcpy_transp_pic(dest + (priv->w << 2), s, w, ih,
priv->w << 3, gif->Image.Width,
transparency, transparent_col);
s += ih * w;
ih = (h - 2 + 3) >> 2;
memcpy_transp_pic(dest + (priv->w << 1), s, w, ih,
priv->w << 2, gif->Image.Width,
transparency, transparent_col);
s += ih * w;
ih = (h - 1 + 1) >> 1;
memcpy_transp_pic(dest + priv->w, s, w, ih,
priv->w << 1, gif->Image.Width,
transparency, transparent_col);
} else
memcpy_transp_pic(dest, buf, w, h, priv->w, gif->Image.Width,
transparency, transparent_col);
if (refmode == 1) memcpy(priv->refimg, dp->buffer, priv->w * priv->h);
if (refmode == 2 && priv->useref) {
dest = priv->refimg + priv->w * t + l;
memset(buf, gif->SBackGroundColor, len);
memcpy_pic(dest, buf, w, h, priv->w, gif->Image.Width);
}
if (!(refmode & 2)) priv->useref = refmode & 1;
}
free(buf);
demuxer->video->dpos++;
dp->pts = ((float)priv->current_pts) / 100;
dp->pos = stream_tell(demuxer->stream);
ds_add_packet(demuxer->video, dp);
return 1;
}
static demuxer_t* demux_open_gif(demuxer_t* demuxer)
{
gif_priv_t *priv = calloc(1, sizeof(gif_priv_t));
sh_video_t *sh_video = NULL;
GifFileType *gif = NULL;
priv->current_pts = 0;
demuxer->seekable = 0; // FIXME
// go back to the beginning
stream_seek(demuxer->stream,demuxer->stream->start_pos);
#ifdef HAVE_GIF_TVT_HACK
// without the TVT functionality of libungif, a hard seek must be
// done to the beginning of the file. this is because libgif is
// unable to use mplayer's cache, and without this lseek libgif will
// not read from the beginning of the file and the command will fail.
// with this hack enabled, you will lose the ability to stream a GIF.
lseek(demuxer->stream->fd, 0, SEEK_SET);
gif = DGifOpenFileHandle(demuxer->stream->fd);
#else
gif = DGifOpen(demuxer->stream, my_read_gif);
#endif
if (!gif) {
PrintGifError();
return NULL;
}
// create a new video stream header
sh_video = new_sh_video(demuxer, 0);
// make sure the demuxer knows about the new video stream header
// (even though new_sh_video() ought to take care of it)
demuxer->video->sh = sh_video;
// make sure that the video demuxer stream header knows about its
// parent video demuxer stream (this is getting wacky), or else
// video_read_properties() will choke
sh_video->ds = demuxer->video;
sh_video->format = mmioFOURCC(8, 'R', 'G', 'B');
sh_video->fps = 5.0f;
sh_video->frametime = 1.0f / sh_video->fps;
sh_video->bih = malloc(sizeof(BITMAPINFOHEADER) + (256 * 4));
sh_video->bih->biCompression = sh_video->format;
sh_video->bih->biWidth = priv->w = (uint16_t)gif->SWidth;
sh_video->bih->biHeight = priv->h = (uint16_t)gif->SHeight;
sh_video->bih->biBitCount = 8;
sh_video->bih->biPlanes = 2;
priv->palette = (unsigned char *)(sh_video->bih + 1);
priv->refimg = malloc(priv->w * priv->h);
priv->gif = gif;
demuxer->priv = priv;
return demuxer;
}
static void demux_close_gif(demuxer_t* demuxer)
{
gif_priv_t *priv = demuxer->priv;
if (!priv) return;
if (priv->gif && DGifCloseFile(priv->gif) == GIF_ERROR)
PrintGifError();
free(priv->refimg);
free(priv);
}
demuxer_desc_t demuxer_desc_gif = {
"GIF demuxer",
"gif",
"GIF",
"Joey Parrish",
"",
DEMUXER_TYPE_GIF,
0, // unsafe autodetect
gif_check_file,
demux_gif_fill_buffer,
demux_open_gif,
demux_close_gif,
NULL,
NULL
};
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