ffmpeg/libavcodec/movtextdec.c

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/*
* 3GPP TS 26.245 Timed Text decoder
* Copyright (c) 2012 Philip Langdale <philipl@overt.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 "avcodec.h"
#include "ass.h"
#include "libavutil/avstring.h"
#include "libavutil/common.h"
#include "libavutil/bprint.h"
#include "libavutil/intreadwrite.h"
static int text_to_ass(AVBPrint *buf, const char *text, const char *text_end)
{
while (text < text_end) {
switch (*text) {
case '\r':
break;
case '\n':
av_bprintf(buf, "\\N");
break;
default:
av_bprint_chars(buf, *text, 1);
break;
}
text++;
}
av_bprintf(buf, "\r\n");
return 0;
}
static int mov_text_init(AVCodecContext *avctx) {
/*
* TODO: Handle the default text style.
* NB: Most players ignore styles completely, with the result that
* it's very common to find files where the default style is broken
* and respecting it results in a worse experience than ignoring it.
*/
return ff_ass_subtitle_header_default(avctx);
}
static int mov_text_decode_frame(AVCodecContext *avctx,
void *data, int *got_sub_ptr, AVPacket *avpkt)
{
AVSubtitle *sub = data;
int ts_start, ts_end;
AVBPrint buf;
const char *ptr = avpkt->data;
const char *end;
if (!ptr || avpkt->size < 2)
return AVERROR_INVALIDDATA;
/*
* A packet of size two with value zero is an empty subtitle
* used to mark the end of the previous non-empty subtitle.
* We can just drop them here as we have duration information
* already. If the value is non-zero, then it's technically a
* bad packet.
*/
if (avpkt->size == 2)
return AV_RB16(ptr) == 0 ? 0 : AVERROR_INVALIDDATA;
/*
* The first two bytes of the packet are the length of the text string
* In complex cases, there are style descriptors appended to the string
* so we can't just assume the packet size is the string size.
*/
end = ptr + FFMIN(2 + AV_RB16(ptr), avpkt->size);
ptr += 2;
ts_start = av_rescale_q(avpkt->pts,
avctx->time_base,
(AVRational){1,100});
ts_end = av_rescale_q(avpkt->pts + avpkt->duration,
avctx->time_base,
(AVRational){1,100});
// Note that the spec recommends lines be no longer than 2048 characters.
av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
text_to_ass(&buf, ptr, end);
if (!av_bprint_is_complete(&buf))
return AVERROR(ENOMEM);
ff_ass_add_rect(sub, buf.str, ts_start, ts_end-ts_start, 0);
*got_sub_ptr = sub->num_rects > 0;
av_bprint_finalize(&buf, NULL);
return avpkt->size;
}
AVCodec ff_movtext_decoder = {
.name = "mov_text",
.long_name = NULL_IF_CONFIG_SMALL("3GPP Timed Text subtitle"),
.type = AVMEDIA_TYPE_SUBTITLE,
Merge commit '36ef5369ee9b336febc2c270f8718cec4476cb85' * commit '36ef5369ee9b336febc2c270f8718cec4476cb85': Replace all CODEC_ID_* with AV_CODEC_ID_* lavc: add AV prefix to codec ids. Conflicts: doc/APIchanges doc/examples/decoding_encoding.c doc/examples/muxing.c ffmpeg.c ffprobe.c ffserver.c libavcodec/8svx.c libavcodec/avcodec.h libavcodec/dnxhd_parser.c libavcodec/dvdsubdec.c libavcodec/error_resilience.c libavcodec/h263dec.c libavcodec/libvorbisenc.c libavcodec/mjpeg_parser.c libavcodec/mjpegenc.c libavcodec/mpeg12.c libavcodec/mpeg4videodec.c libavcodec/mpegvideo.c libavcodec/mpegvideo_enc.c libavcodec/pcm.c libavcodec/r210dec.c libavcodec/utils.c libavcodec/v210dec.c libavcodec/version.h libavdevice/alsa-audio-dec.c libavdevice/bktr.c libavdevice/v4l2.c libavformat/asfdec.c libavformat/asfenc.c libavformat/avformat.h libavformat/avidec.c libavformat/caf.c libavformat/electronicarts.c libavformat/flacdec.c libavformat/flvdec.c libavformat/flvenc.c libavformat/framecrcenc.c libavformat/img2.c libavformat/img2dec.c libavformat/img2enc.c libavformat/ipmovie.c libavformat/isom.c libavformat/matroska.c libavformat/matroskadec.c libavformat/matroskaenc.c libavformat/mov.c libavformat/movenc.c libavformat/mp3dec.c libavformat/mpeg.c libavformat/mpegts.c libavformat/mxf.c libavformat/mxfdec.c libavformat/mxfenc.c libavformat/nsvdec.c libavformat/nut.c libavformat/oggenc.c libavformat/pmpdec.c libavformat/rawdec.c libavformat/rawenc.c libavformat/riff.c libavformat/sdp.c libavformat/utils.c libavformat/vocenc.c libavformat/wtv.c libavformat/xmv.c Merged-by: Michael Niedermayer <michaelni@gmx.at>
2012-08-07 20:45:46 +00:00
.id = AV_CODEC_ID_MOV_TEXT,
.init = mov_text_init,
.decode = mov_text_decode_frame,
};