ffmpeg/libavcodec/samidec.c

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2012-06-17 09:42:47 +00:00
/*
* Copyright (c) 2012 Clément Bœsch
*
* 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
*/
/**
* @file
* SAMI subtitle decoder
* @see http://msdn.microsoft.com/en-us/library/ms971327.aspx
*/
#include "ass.h"
#include "libavutil/avstring.h"
#include "libavutil/bprint.h"
typedef struct {
AVBPrint source;
AVBPrint content;
AVBPrint full;
} SAMIContext;
static int sami_paragraph_to_ass(AVCodecContext *avctx, const char *src)
{
SAMIContext *sami = avctx->priv_data;
int ret = 0;
char *tag = NULL;
char *dupsrc = av_strdup(src);
char *p = dupsrc;
av_bprint_clear(&sami->content);
for (;;) {
char *saveptr = NULL;
int prev_chr_is_space = 0;
AVBPrint *dst = &sami->content;
/* parse & extract paragraph tag */
p = av_stristr(p, "<P");
if (!p)
break;
if (p[2] != '>' && !isspace(p[2])) { // avoid confusion with tags such as <PRE>
p++;
continue;
}
if (dst->len) // add a separator with the previous paragraph if there was one
av_bprintf(dst, "\\N");
tag = av_strtok(p, ">", &saveptr);
if (!tag || !saveptr)
break;
p = saveptr;
/* check if the current paragraph is the "source" (speaker name) */
if (av_stristr(tag, "ID=Source") || av_stristr(tag, "ID=\"Source\"")) {
dst = &sami->source;
av_bprint_clear(dst);
}
/* if empty event -> skip subtitle */
while (isspace(*p))
p++;
if (!strncmp(p, "&nbsp;", 6)) {
ret = -1;
goto end;
}
/* extract the text, stripping most of the tags */
while (*p) {
if (*p == '<') {
if (!av_strncasecmp(p, "<P", 2) && (p[2] == '>' || isspace(p[2])))
break;
if (!av_strncasecmp(p, "<BR", 3))
av_bprintf(dst, "\\N");
p++;
while (*p && *p != '>')
p++;
if (!*p)
break;
if (*p == '>')
p++;
}
if (!isspace(*p))
av_bprint_chars(dst, *p, 1);
else if (!prev_chr_is_space)
av_bprint_chars(dst, ' ', 1);
prev_chr_is_space = isspace(*p);
p++;
}
}
av_bprint_clear(&sami->full);
if (sami->source.len)
av_bprintf(&sami->full, "{\\i1}%s{\\i0}\\N", sami->source.str);
av_bprintf(&sami->full, "%s\r\n", sami->content.str);
end:
av_free(dupsrc);
return ret;
}
static int sami_decode_frame(AVCodecContext *avctx,
void *data, int *got_sub_ptr, AVPacket *avpkt)
{
AVSubtitle *sub = data;
const char *ptr = avpkt->data;
SAMIContext *sami = avctx->priv_data;
if (ptr && avpkt->size > 0 && !sami_paragraph_to_ass(avctx, ptr)) {
int ts_start = av_rescale_q(avpkt->pts, avctx->time_base, (AVRational){1,100});
int ts_duration = avpkt->duration != -1 ?
av_rescale_q(avpkt->duration, avctx->time_base, (AVRational){1,100}) : -1;
ff_ass_add_rect(sub, sami->full.str, ts_start, ts_duration, 0);
}
*got_sub_ptr = sub->num_rects > 0;
return avpkt->size;
}
static av_cold int sami_init(AVCodecContext *avctx)
{
SAMIContext *sami = avctx->priv_data;
av_bprint_init(&sami->source, 0, 2048);
av_bprint_init(&sami->content, 0, 2048);
av_bprint_init(&sami->full, 0, 2048);
return ff_ass_subtitle_header_default(avctx);
}
static av_cold int sami_close(AVCodecContext *avctx)
{
SAMIContext *sami = avctx->priv_data;
av_bprint_finalize(&sami->source, NULL);
av_bprint_finalize(&sami->content, NULL);
av_bprint_finalize(&sami->full, NULL);
return 0;
}
AVCodec ff_sami_decoder = {
.name = "sami",
.long_name = NULL_IF_CONFIG_SMALL("SAMI subtitle"),
.type = AVMEDIA_TYPE_SUBTITLE,
.id = CODEC_ID_SAMI,
.priv_data_size = sizeof(SAMIContext),
.init = sami_init,
.close = sami_close,
.decode = sami_decode_frame,
};