lavf: add internal demuxer helpers for subtitles.

libavformat/Makefile

@@ -19,6 +19,7 @@ OBJS = allformats.o         \
        riff.o               \
        sdp.o                \
        seek.o               \
+       subtitles.o          \
        utils.o              \
 
 OBJS-$(CONFIG_NETWORK)                   += network.o

libavformat/subtitles.c

@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2012 Clément Bœsch
+ *
+ * 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 "subtitles.h"
+
+AVPacket *ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q,
+                                    const uint8_t *event, int len, int merge)
+{
+    AVPacket *subs, *sub;
+
+    if (merge && q->nb_subs > 0) {
+        /* merge with previous event */
+
+        int old_len;
+        sub = &q->subs[q->nb_subs - 1];
+        old_len = sub->size;
+        if (av_grow_packet(sub, len) < 0)
+            return NULL;
+        memcpy(sub->data + old_len, event, len);
+    } else {
+        /* new event */
+
+        if (q->nb_subs >= INT_MAX/sizeof(*q->subs) - 1)
+            return NULL;
+        subs = av_fast_realloc(q->subs, &q->allocated_size,
+                               (q->nb_subs + 1) * sizeof(*q->subs));
+        if (!subs)
+            return NULL;
+        q->subs = subs;
+        sub = &subs[q->nb_subs++];
+        if (av_new_packet(sub, len) < 0)
+            return NULL;
+        sub->destruct = NULL;
+        sub->flags |= AV_PKT_FLAG_KEY;
+        sub->pts = sub->dts = 0;
+        memcpy(sub->data, event, len);
+    }
+    return sub;
+}
+
+static int cmp_pkt_sub(const void *a, const void *b)
+{
+    const AVPacket *s1 = a;
+    const AVPacket *s2 = b;
+    if (s1->pts == s2->pts) {
+        if (s1->pos == s2->pos)
+            return 0;
+        return s1->pos > s2->pos ? 1 : -1;
+    }
+    return s1->pts > s2->pts ? 1 : -1;
+}
+
+void ff_subtitles_queue_finalize(FFDemuxSubtitlesQueue *q)
+{
+    int i;
+
+    qsort(q->subs, q->nb_subs, sizeof(*q->subs), cmp_pkt_sub);
+    for (i = 0; i < q->nb_subs; i++)
+        if (q->subs[i].duration == -1 && i < q->nb_subs - 1)
+            q->subs[i].duration = q->subs[i + 1].pts - q->subs[i].pts;
+}
+
+int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt)
+{
+    AVPacket *sub = q->subs + q->current_sub_idx;
+
+    if (q->current_sub_idx == q->nb_subs)
+        return AVERROR_EOF;
+    *pkt = *sub;
+    pkt->dts = pkt->pts;
+    q->current_sub_idx++;
+    return 0;
+}
+
+void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
+{
+    int i;
+
+    for (i = 0; i < q->nb_subs; i++)
+        av_destruct_packet(&q->subs[i]);
+    av_freep(&q->subs);
+    q->nb_subs = q->allocated_size = q->current_sub_idx = 0;
+}

libavformat/subtitles.h

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2012 Clément Bœsch
+ *
+ * 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
+ */
+
+#ifndef AVFORMAT_SUBTITLES_H
+#define AVFORMAT_SUBTITLES_H
+
+#include <stdint.h>
+#include "avformat.h"
+
+typedef struct {
+    AVPacket *subs;         ///< array of subtitles packets
+    int nb_subs;            ///< number of subtitles packets
+    int allocated_size;     ///< allocated size for subs
+    int current_sub_idx;    ///< current position for the read packet callback
+} FFDemuxSubtitlesQueue;
+
+/**
+ * Insert a new subtitle event.
+ *
+ * @param event the subtitle line, may not be zero terminated
+ * @param len   the length of the event (in strlen() sense, so without '\0')
+ * @param merge set to 1 if the current event should be concatenated with the
+ *              previous one instead of adding a new entry, 0 otherwise
+ */
+AVPacket *ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q,
+                                    const uint8_t *event, int len, int merge);
+
+/**
+ * Set missing durations and sort subtitles by PTS, and then byte position.
+ */
+void ff_subtitles_queue_finalize(FFDemuxSubtitlesQueue *q);
+
+/**
+ * Generic read_packet() callback for subtitles demuxers using this queue
+ * system.
+ */
+int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt);
+
+/**
+ * Remove and destroy all the subtitles packets.
+ */
+void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q);
+
+#endif /* AVFORMAT_SUBTITLES_H */