ffmpeg/libavcodec/assdec.c

121 lines
3.7 KiB
C

/*
* SSA/ASS decoder
* Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
*
* 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
*/
#include <string.h>
#include "avcodec.h"
#include "ass.h"
#include "ass_split.h"
#include "libavutil/internal.h"
#include "libavutil/mem.h"
static av_cold int ass_decode_init(AVCodecContext *avctx)
{
avctx->subtitle_header = av_malloc(avctx->extradata_size + 1);
if (!avctx->subtitle_header)
return AVERROR(ENOMEM);
memcpy(avctx->subtitle_header, avctx->extradata, avctx->extradata_size);
avctx->subtitle_header[avctx->extradata_size] = 0;
avctx->subtitle_header_size = avctx->extradata_size;
avctx->priv_data = ff_ass_split(avctx->extradata);
if(!avctx->priv_data)
return -1;
return 0;
}
static int ass_decode_close(AVCodecContext *avctx)
{
ff_ass_split_free(avctx->priv_data);
avctx->priv_data = NULL;
return 0;
}
#if CONFIG_SSA_DECODER
static int ssa_decode_frame(AVCodecContext *avctx, void *data, int *got_sub_ptr,
AVPacket *avpkt)
{
const char *ptr = avpkt->data;
int len, size = avpkt->size;
while (size > 0) {
int duration;
ASSDialog *dialog = ff_ass_split_dialog(avctx->priv_data, ptr, 0, NULL);
if (!dialog)
return AVERROR_INVALIDDATA;
duration = dialog->end - dialog->start;
len = ff_ass_add_rect(data, ptr, 0, duration, 1);
if (len < 0)
return len;
ptr += len;
size -= len;
}
*got_sub_ptr = avpkt->size > 0;
return avpkt->size;
}
AVCodec ff_ssa_decoder = {
.name = "ssa",
.long_name = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
.type = AVMEDIA_TYPE_SUBTITLE,
.id = AV_CODEC_ID_SSA,
.init = ass_decode_init,
.decode = ssa_decode_frame,
.close = ass_decode_close,
};
#endif
#if CONFIG_ASS_DECODER
static int ass_decode_frame(AVCodecContext *avctx, void *data, int *got_sub_ptr,
AVPacket *avpkt)
{
int ret;
AVSubtitle *sub = data;
const char *ptr = avpkt->data;
static const AVRational ass_tb = {1, 100};
const int ts_start = av_rescale_q(avpkt->pts, avctx->time_base, ass_tb);
const int ts_duration = av_rescale_q(avpkt->duration, avctx->time_base, ass_tb);
if (avpkt->size <= 0)
return avpkt->size;
ret = ff_ass_add_rect(sub, ptr, ts_start, ts_duration, 2);
if (ret < 0) {
if (ret == AVERROR_INVALIDDATA)
av_log(avctx, AV_LOG_ERROR, "Invalid ASS packet\n");
return ret;
}
*got_sub_ptr = avpkt->size > 0;
return avpkt->size;
}
AVCodec ff_ass_decoder = {
.name = "ass",
.long_name = NULL_IF_CONFIG_SMALL("ASS (Advanced SubStation Alpha) subtitle"),
.type = AVMEDIA_TYPE_SUBTITLE,
.id = AV_CODEC_ID_ASS,
.init = ass_decode_init,
.decode = ass_decode_frame,
.close = ass_decode_close,
};
#endif