[FFmpeg-devel] [PATCH] avcodec: add HDMV Text Subtitle decoder
Paul B Mahol
onemda at gmail.com
Tue Jan 31 16:22:17 EET 2017
Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
libavcodec/Makefile | 2 +
libavcodec/allcodecs.c | 2 +
libavcodec/textst_parser.c | 49 ++++++++++++++++++++
libavcodec/textstdec.c | 108 +++++++++++++++++++++++++++++++++++++++++++++
libavformat/utils.c | 1 +
5 files changed, 162 insertions(+)
create mode 100644 libavcodec/textst_parser.c
create mode 100644 libavcodec/textstdec.c
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 43a6add..edadb0f 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -539,6 +539,7 @@ OBJS-$(CONFIG_SVQ1_ENCODER) += svq1enc.o svq1.o h263data.o \
OBJS-$(CONFIG_SVQ3_DECODER) += svq3.o svq13.o mpegutils.o h264data.o
OBJS-$(CONFIG_TEXT_DECODER) += textdec.o ass.o
OBJS-$(CONFIG_TEXT_ENCODER) += srtenc.o ass_split.o
+OBJS-$(CONFIG_TEXTST_DECODER) += textstdec.o ass.o
OBJS-$(CONFIG_TAK_DECODER) += takdec.o tak.o takdsp.o
OBJS-$(CONFIG_TARGA_DECODER) += targa.o
OBJS-$(CONFIG_TARGA_ENCODER) += targaenc.o rle.o
@@ -945,6 +946,7 @@ OBJS-$(CONFIG_RV30_PARSER) += rv34_parser.o
OBJS-$(CONFIG_RV40_PARSER) += rv34_parser.o
OBJS-$(CONFIG_SIPR_PARSER) += sipr_parser.o
OBJS-$(CONFIG_TAK_PARSER) += tak_parser.o tak.o
+OBJS-$(CONFIG_TEXTST_PARSER) += textst_parser.o
OBJS-$(CONFIG_VC1_PARSER) += vc1_parser.o vc1.o vc1data.o \
simple_idct.o wmv2data.o
OBJS-$(CONFIG_VP3_PARSER) += vp3_parser.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index f92b2b7..9a90533 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -581,6 +581,7 @@ void avcodec_register_all(void)
REGISTER_DECODER(SUBVIEWER, subviewer);
REGISTER_DECODER(SUBVIEWER1, subviewer1);
REGISTER_ENCDEC (TEXT, text);
+ REGISTER_DECODER(TEXTST, textst);
REGISTER_DECODER(VPLAYER, vplayer);
REGISTER_ENCDEC (WEBVTT, webvtt);
REGISTER_ENCDEC (XSUB, xsub);
@@ -704,6 +705,7 @@ void avcodec_register_all(void)
REGISTER_PARSER(RV40, rv40);
REGISTER_PARSER(SIPR, sipr);
REGISTER_PARSER(TAK, tak);
+ REGISTER_PARSER(TEXTST, textst);
REGISTER_PARSER(VC1, vc1);
REGISTER_PARSER(VORBIS, vorbis);
REGISTER_PARSER(VP3, vp3);
diff --git a/libavcodec/textst_parser.c b/libavcodec/textst_parser.c
new file mode 100644
index 0000000..5079a96
--- /dev/null
+++ b/libavcodec/textst_parser.c
@@ -0,0 +1,49 @@
+/*
+ * 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
+ * HDMV TextST subtitle parser
+ */
+
+#include "libavutil/intreadwrite.h"
+#include "parser.h"
+
+static int textst_parse(AVCodecParserContext *s1, AVCodecContext *avctx,
+ const uint8_t **poutbuf, int *poutbuf_size,
+ const uint8_t *buf, int buf_size)
+{
+ if (buf_size > 13) {
+ int64_t end;
+
+ s1->pts = ((int64_t)(buf[3] & 1) << 32) | AV_RB32(&buf[4]);
+ end = ((int64_t)(buf[8] & 1) << 32) | AV_RB32(&buf[9]);
+ s1->duration = (end - s1->pts);
+ }
+
+ /* always return the full packet. this parser isn't doing any splitting or
+ combining, only packet analysis */
+ *poutbuf = buf;
+ *poutbuf_size = buf_size;
+ return buf_size;
+}
+
+AVCodecParser ff_textst_parser = {
+ .codec_ids = { AV_CODEC_ID_HDMV_TEXT_SUBTITLE },
+ .parser_parse = textst_parse,
+};
diff --git a/libavcodec/textstdec.c b/libavcodec/textstdec.c
new file mode 100644
index 0000000..a259d2d
--- /dev/null
+++ b/libavcodec/textstdec.c
@@ -0,0 +1,108 @@
+/*
+ * HDMV TextST decoder
+ * Copyright (c) 2017 Paul B Mahol
+ *
+ * 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 "libavutil/bprint.h"
+#include "avcodec.h"
+#include "ass.h"
+#include "bytestream.h"
+
+static int textst_event_to_ass(AVBPrint *buf, const char *p, int size)
+{
+ GetByteContext gb;
+ int i, count;
+
+ bytestream2_init(&gb, p, size);
+ count = bytestream2_get_byte(&gb);
+
+ if (count > 127) {
+ int size = bytestream2_get_be16(&gb);
+ bytestream2_skip(&gb, size);
+ }
+ if (bytestream2_get_bytes_left(&gb) > 2) {
+ count = bytestream2_get_byte(&gb);
+
+ for (i = 0; i < count; i++) {
+ int dlength;
+
+ bytestream2_skip(&gb, 2);
+ dlength = bytestream2_get_be16(&gb);
+
+ while (dlength > 3) {
+ int type, length;
+ int code = bytestream2_get_byte(&gb);
+
+ dlength--;
+ if (code != 0x1b)
+ continue;
+
+ type = bytestream2_get_byte(&gb);
+ length = bytestream2_get_byte(&gb);
+ dlength -= (2 + length);
+
+ switch (type) {
+ case 1:
+ av_bprint_append_data(buf, gb.buffer, FFMIN(length, bytestream2_get_bytes_left(&gb)));
+ bytestream2_skip(&gb, length);
+ break;
+ case 0x0a:
+ av_bprintf(buf, "\n");
+ default:
+ bytestream2_skip(&gb, length);
+ break;
+ }
+ }
+ }
+ }
+
+ return 0;
+}
+
+static int textst_decode_frame(AVCodecContext *avctx,
+ void *data, int *got_sub_ptr, AVPacket *avpkt)
+{
+ FFASSDecoderContext *s = avctx->priv_data;
+ const char *ptr = avpkt->data;
+ AVSubtitle *sub = data;
+ AVBPrint buf;
+ int ret = 0;
+
+ av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
+ if (ptr && avpkt->size > 13 && !textst_event_to_ass(&buf, ptr + 13, avpkt->size - 13))
+ ret = ff_ass_add_rect(sub, buf.str, s->readorder++, 0, NULL, NULL);
+ av_bprint_finalize(&buf, NULL);
+ if (ret < 0)
+ return ret;
+ *got_sub_ptr = sub->num_rects > 0;
+ return avpkt->size;
+}
+
+AVCodec ff_textst_decoder = {
+ .name = "textst",
+ .long_name = NULL_IF_CONFIG_SMALL("HDMV TextST subtitle"),
+ .type = AVMEDIA_TYPE_SUBTITLE,
+ .id = AV_CODEC_ID_HDMV_TEXT_SUBTITLE,
+ .decode = textst_decode_frame,
+ .init = ff_ass_subtitle_header_default,
+ .flush = ff_ass_decoder_flush,
+ .priv_data_size = sizeof(FFASSDecoderContext),
+};
diff --git a/libavformat/utils.c b/libavformat/utils.c
index 0711310..74f808f 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -1445,6 +1445,7 @@ static int parse_packet(AVFormatContext *s, AVPacket *pkt, int stream_index)
out_pkt.stream_index = st->index;
out_pkt.pts = st->parser->pts;
+ out_pkt.duration = st->parser->duration;
out_pkt.dts = st->parser->dts;
out_pkt.pos = st->parser->pos;
--
2.9.3
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