[Ffmpeg-devel] [PATCH] TTA Seeking

[David Conrad]

Hi,

The following patch adds support for seeking in TTA files.

-David

Index: libavformat/tta.c
===================================================================
--- libavformat/tta.c	(revision 8728)
+++ libavformat/tta.c	(working copy)
@@ -23,7 +23,6 @@
typedef struct {
      int totalframes, currentframe;
-    uint32_t *seektable;
} TTAContext;
static int tta_probe(AVProbeData *p)
@@ -39,6 +38,7 @@
      TTAContext *c = s->priv_data;
      AVStream *st;
      int i, channels, bps, samplerate, datalen, framelen;
+    uint64_t framepos;
      if (get_le32(&s->pb) != ff_get_fourcc("TTA1"))
          return -1; // not tta file
@@ -68,16 +68,21 @@
          av_log(s, AV_LOG_ERROR, "totalframes too large\n");
          return -1;
      }
-    c->seektable = av_mallocz(sizeof(uint32_t)*c->totalframes);
-    if (!c->seektable)
-        return AVERROR_NOMEM;
-    for (i = 0; i < c->totalframes; i++)
-        c->seektable[i] = get_le32(&s->pb);
+    st = av_new_stream(s, 0);
+    av_set_pts_info(st, 64, 1, samplerate);
+    st->start_time = 0;
+    st->duration = datalen;
+
+    framepos = url_ftell(&s->pb) + 4*c->totalframes + 4;
+
+    for (i = 0; i < c->totalframes; i++) {
+        uint32_t size = get_le32(&s->pb);
+        av_add_index_entry(st, framepos, i*framelen, size, 0,  
AVINDEX_KEYFRAME);
+        framepos += size;
+    }
      url_fskip(&s->pb, 4); // seektable crc
-    st = av_new_stream(s, 0);
-//    av_set_pts_info(st, 32, 1, 1000);
      if (!st)
          return AVERROR_NOMEM;
      st->codec->codec_type = CODEC_TYPE_AUDIO;
@@ -102,37 +107,29 @@
static int tta_read_packet(AVFormatContext *s, AVPacket *pkt)
{
      TTAContext *c = s->priv_data;
-    int ret, size;
+    AVStream *st = s->streams[0];
+    int size;
      // FIXME!
      if (c->currentframe > c->totalframes)
-        size = 0;
-    else
-        size = c->seektable[c->currentframe];
+        return -1;
-    c->currentframe++;
+    size = st->index_entries[c->currentframe++].size;
-    if (av_new_packet(pkt, size) < 0)
-        return AVERROR_IO;
-
-    pkt->pos = url_ftell(&s->pb);
-    pkt->stream_index = 0;
-    ret = get_buffer(&s->pb, pkt->data, size);
-    if (ret <= 0) {
-        av_free_packet(pkt);
-        return AVERROR_IO;
-    }
-    pkt->size = ret;
-//    av_log(s, AV_LOG_INFO, "TTA packet #%d desired size: %d read  
size: %d at pos %d\n",
-//        c->currentframe, size, ret, pkt->pos);
-    return 0; //ret;
+    return av_get_packet(&s->pb, pkt, size);
}
-static int tta_read_close(AVFormatContext *s)
+static int tta_read_seek(AVFormatContext *s, int stream_index,  
int64_t timestamp, int flags)
{
      TTAContext *c = s->priv_data;
-    if (c->seektable)
-        av_free(c->seektable);
+    AVStream *st = s->streams[stream_index];
+    int index = av_index_search_timestamp(st, timestamp, flags);
+    if (index < 0)
+        return -1;
+
+    c->currentframe = index;
+    url_fseek(&s->pb, st->index_entries[index].pos, SEEK_SET);
+
      return 0;
}
@@ -143,6 +140,7 @@
      tta_probe,
      tta_read_header,
      tta_read_packet,
-    tta_read_close,
+    NULL,
+    tta_read_seek,
      .extensions = "tta",
};