Added STL demuxer and decoder

Signed-off-by: Clément Bœsch <u@pkh.me>

1 files changed, 141 insertions, 0 deletions

diff --git a/libavformat/stldec.c b/libavformat/stldec.c
new file mode 100644
index 0000000000..b84c7e9eb0
--- /dev/null
+++ b/libavformat/stldec.c
@@ -0,0 +1,141 @@
+/*
+ * Copyright (c) 2014 Eejya Singh
+ *
+ * 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
+ * STL subtitles format demuxer
+ * @see https://documentation.apple.com/en/dvdstudiopro/usermanual/index.html#chapter=19%26section=13%26tasks=true
+ */
+
+#include "avformat.h"
+#include "internal.h"
+#include "subtitles.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/avstring.h"
+
+typedef struct {
+    FFDemuxSubtitlesQueue q;
+} STLContext;
+
+static int stl_probe(AVProbeData *p)
+{
+    char c;
+    const unsigned char *ptr = p->buf;
+
+    if (AV_RB24(ptr) == 0xEFBBBF)
+        ptr += 3;  /* skip UTF-8 BOM */
+
+    while (*ptr == '\r' || *ptr == '\n' || *ptr == '$' || !strncmp(ptr, "//" , 2))
+        ptr += ff_subtitles_next_line(ptr);
+
+    if (sscanf(ptr, "%*d:%*d:%*d:%*d , %*d:%*d:%*d:%*d , %c", &c) == 1)
+        return AVPROBE_SCORE_MAX;
+
+    return 0;
+}
+
+static int64_t get_pts(char **buf, int *duration)
+{
+    int hh1, mm1, ss1, ms1;
+    int hh2, mm2, ss2, ms2;
+    int len = 0;
+
+    if (sscanf(*buf, "%2d:%2d:%2d:%2d , %2d:%2d:%2d:%2d , %n",
+                &hh1, &mm1, &ss1, &ms1,
+                &hh2, &mm2, &ss2, &ms2, &len) >= 8 && len > 0) {
+        int64_t start = (hh1*3600LL + mm1*60LL + ss1) * 100LL + ms1;
+        int64_t end = (hh2*3600LL + mm2*60LL + ss2) * 100LL + ms2;
+        *duration = end - start;
+        *buf += len;
+        return start;
+    }
+    return AV_NOPTS_VALUE;
+}
+
+static int stl_read_header(AVFormatContext *s)
+{
+    STLContext *stl = s->priv_data;
+    AVStream *st = avformat_new_stream(s, NULL);
+
+    if (!st)
+        return AVERROR(ENOMEM);
+    avpriv_set_pts_info(st, 64, 1, 100);
+    st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
+    st->codec->codec_id   = AV_CODEC_ID_STL;
+
+    while (!avio_feof(s->pb)) {
+        char line[4096];
+        char *p = line;
+        const int64_t pos = avio_tell(s->pb);
+        int len = ff_get_line(s->pb, line, sizeof(line));
+        int64_t pts_start;
+        int duration;
+
+        if (!len)
+            break;
+
+        line[strcspn(line, "\r\n")] = 0;
+        pts_start = get_pts(&p , &duration);
+
+        if (pts_start != AV_NOPTS_VALUE) {
+            AVPacket *sub;
+            sub = ff_subtitles_queue_insert(&stl->q, p, strlen(p), 0);
+            if (!sub)
+                return AVERROR(ENOMEM);
+            sub->pos = pos;
+            sub->pts = pts_start;
+            sub->duration = duration;
+        }
+    }
+    ff_subtitles_queue_finalize(&stl->q);
+    return 0;
+}
+static int stl_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    STLContext *stl = s->priv_data;
+    return ff_subtitles_queue_read_packet(&stl->q, pkt);
+}
+
+static int stl_read_seek(AVFormatContext *s, int stream_index,
+                             int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
+{
+    STLContext *stl = s->priv_data;
+    return ff_subtitles_queue_seek(&stl->q, s, stream_index,
+                                   min_ts, ts, max_ts, flags);
+}
+
+static int stl_read_close(AVFormatContext *s)
+{
+    STLContext *stl = s->priv_data;
+    ff_subtitles_queue_clean(&stl->q);
+    return 0;
+}
+
+AVInputFormat ff_stl_demuxer = {
+    .name           = "stl",
+    .long_name      = NULL_IF_CONFIG_SMALL("Spruce subtitle format"),
+    .priv_data_size = sizeof(STLContext),
+    .read_probe     = stl_probe,
+    .read_header    = stl_read_header,
+    .read_packet    = stl_read_packet,
+    .read_seek2     = stl_read_seek,
+    .read_close     = stl_read_close,
+    .extensions     = "stl",
+};