add MicroDVD muxer and demuxer

Signed-off-by: Aurelien Jacobs <aurel@gnuage.org>
2010-09-10 23:10:53 +02:00
parent deff8a6d3a
commit 3c9bfb3368
9 changed files with 188 additions and 1 deletions
--- a/libavformat/microdvddec.c
+++ b/libavformat/microdvddec.c
@@ -0,0 +1,129 @@
+/*
+ * MicroDVD subtitle demuxer
+ * 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 "avformat.h"
+#include "internal.h"
+#include "libavutil/intreadwrite.h"
+
+#define MAX_LINESIZE 2048
+
+
+typedef struct {
+    uint8_t lines[3][MAX_LINESIZE];
+    int64_t pos[3];
+} MicroDVDContext;
+
+
+static int microdvd_probe(AVProbeData *p)
+{
+    unsigned char c, *ptr = p->buf;
+    int i;
+
+    if (AV_RB24(ptr) == 0xEFBBBF)
+        ptr += 3;  /* skip UTF-8 BOM */
+
+    for (i=0; i<3; i++) {
+        if (sscanf(ptr, "{%*d}{}%c",     &c) != 1 &&
+            sscanf(ptr, "{%*d}{%*d}%c",  &c) != 1 &&
+            sscanf(ptr, "{DEFAULT}{}%c", &c) != 1)
+            return 0;
+        ptr += strcspn(ptr, "\n") + 1;
+    }
+    return AVPROBE_SCORE_MAX;
+}
+
+static int microdvd_read_header(AVFormatContext *s, AVFormatParameters *ap)
+{
+    AVRational pts_info = (AVRational){ 2997, 125 };  /* default: 23.976 fps */
+    MicroDVDContext *microdvd = s->priv_data;
+    AVStream *st = av_new_stream(s, 0);
+    int i, frame;
+    double fps;
+    char c;
+
+    if (!st)
+        return -1;
+    for (i=0; i<FF_ARRAY_ELEMS(microdvd->lines); i++) {
+        microdvd->pos[i] = avio_tell(s->pb);
+        ff_get_line(s->pb, microdvd->lines[i], sizeof(microdvd->lines[i]));
+        if ((sscanf(microdvd->lines[i], "{%d}{}%6lf",    &frame, &fps) == 2 ||
+             sscanf(microdvd->lines[i], "{%d}{%*d}%6lf", &frame, &fps) == 2)
+            && frame <= 1 && fps > 3 && fps < 100)
+            pts_info = av_d2q(fps, 100000);
+        if (sscanf(microdvd->lines[i], "{DEFAULT}{}%c", &c) == 1) {
+            st->codec->extradata = av_strdup(microdvd->lines[i] + 11);
+            st->codec->extradata_size = strlen(st->codec->extradata);
+            i--;
+        }
+    }
+    av_set_pts_info(st, 64, pts_info.den, pts_info.num);
+    st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
+    st->codec->codec_id   = CODEC_ID_MICRODVD;
+    return 0;
+}
+
+static int64_t get_pts(const char *buf)
+{
+    int frame;
+    char c;
+
+    if (sscanf(buf, "{%d}{%c", &frame, &c) == 2)
+        return frame;
+    return AV_NOPTS_VALUE;
+}
+
+static int microdvd_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    MicroDVDContext *microdvd = s->priv_data;
+    char buffer[MAX_LINESIZE];
+    int64_t pos = avio_tell(s->pb);
+    int i, len = 0, res = AVERROR_EOF;
+
+    for (i=0; i<FF_ARRAY_ELEMS(microdvd->lines); i++) {
+        if (microdvd->lines[i][0]) {
+            strcpy(buffer, microdvd->lines[i]);
+            pos = microdvd->pos[i];
+            len = strlen(buffer);
+            microdvd->lines[i][0] = 0;
+            break;
+        }
+    }
+    if (!len)
+        len = ff_get_line(s->pb, buffer, sizeof(buffer));
+
+    if (buffer[0] && !(res = av_new_packet(pkt, len))) {
+        memcpy(pkt->data, buffer, len);
+        pkt->flags |= AV_PKT_FLAG_KEY;
+        pkt->pos = pos;
+        pkt->pts = pkt->dts = get_pts(buffer);
+    }
+    return res;
+}
+
+AVInputFormat ff_microdvd_demuxer = {
+    .name           = "microdvd",
+    .long_name      = NULL_IF_CONFIG_SMALL("MicroDVD subtitle format"),
+    .priv_data_size = sizeof(MicroDVDContext),
+    .read_probe     = microdvd_probe,
+    .read_header    = microdvd_read_header,
+    .read_packet    = microdvd_read_packet,
+    .flags          = AVFMT_GENERIC_INDEX,
+};