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authorJoakim Plate <elupus@ecce.se>2011-09-12 19:33:31 +0200
committerJoakim Plate <elupus@ecce.se>2011-09-18 18:16:37 +0200
commit7768f6b1b91b0046e51d02c70b31a1c7766bd4d7 (patch)
tree273d925a229615ccb51a1de0514b3d43f44534e7
parent46f415b5533feffd92ccda8cb15670cd70a2963d (diff)
downloadffmpeg-7768f6b1b91b0046e51d02c70b31a1c7766bd4d7.tar.gz
add support for generic seeking by reading timestamps in nuv
-rw-r--r--libavformat/nuv.c76
1 files changed, 76 insertions, 0 deletions
diff --git a/libavformat/nuv.c b/libavformat/nuv.c
index 607dcdc201..20ca472673 100644
--- a/libavformat/nuv.c
+++ b/libavformat/nuv.c
@@ -258,6 +258,81 @@ static int nuv_packet(AVFormatContext *s, AVPacket *pkt) {
return AVERROR(EIO);
}
+/**
+ * \brief looks for the string RTjjjjjjjjjj in the stream too resync reading
+ * \return 1 if the syncword is found 0 otherwise.
+ */
+static int nuv_resync(AVFormatContext *s, int64_t pos_limit) {
+ AVIOContext *pb = s->pb;
+ uint32_t tag = 0;
+ while(!url_feof(pb) && avio_tell(pb) < pos_limit) {
+ tag = (tag << 8) | avio_r8(pb);
+ if (tag == MKBETAG('R','T','j','j') &&
+ (tag = avio_rb32(pb)) == MKBETAG('j','j','j','j') &&
+ (tag = avio_rb32(pb)) == MKBETAG('j','j','j','j'))
+ return 1;
+ }
+ return 0;
+}
+
+/**
+ * \brief attempts to read a timestamp from stream at the given stream position
+ * \return timestamp if successfull and AV_NOPTS_VALUE if failure
+ */
+static int64_t nuv_read_dts(AVFormatContext *s, int stream_index,
+ int64_t *ppos, int64_t pos_limit)
+{
+ NUVContext *ctx = s->priv_data;
+ AVIOContext *pb = s->pb;
+ uint8_t hdr[HDRSIZE];
+ nuv_frametype frametype;
+ int size, key, idx;
+ int64_t pos, dts;
+
+ if (avio_seek(pb, *ppos, SEEK_SET) < 0)
+ return AV_NOPTS_VALUE;
+
+ if (!nuv_resync(s, pos_limit))
+ return AV_NOPTS_VALUE;
+
+ while (!url_feof(pb) && avio_tell(pb) < pos_limit) {
+ if (avio_read(pb, hdr, HDRSIZE) < HDRSIZE)
+ return AV_NOPTS_VALUE;
+ frametype = hdr[0];
+ size = PKTSIZE(AV_RL32(&hdr[8]));
+ switch (frametype) {
+ case NUV_SEEKP:
+ break;
+ case NUV_AUDIO:
+ case NUV_VIDEO:
+ if (frametype == NUV_VIDEO) {
+ idx = ctx->v_id;
+ key = hdr[2] == 0;
+ } else {
+ idx = ctx->a_id;
+ key = 1;
+ }
+ if (stream_index == idx) {
+
+ pos = avio_tell(s->pb) - HDRSIZE;
+ dts = AV_RL32(&hdr[4]);
+
+ // TODO - add general support in av_gen_search, so it adds positions after reading timestamps
+ av_add_index_entry(s->streams[stream_index], pos, dts, size + HDRSIZE, 0,
+ key ? AVINDEX_KEYFRAME : 0);
+
+ *ppos = pos;
+ return dts;
+ }
+ default:
+ avio_skip(pb, size);
+ break;
+ }
+ }
+ return AV_NOPTS_VALUE;
+}
+
+
AVInputFormat ff_nuv_demuxer = {
.name = "nuv",
.long_name = NULL_IF_CONFIG_SMALL("NuppelVideo format"),
@@ -265,5 +340,6 @@ AVInputFormat ff_nuv_demuxer = {
.read_probe = nuv_probe,
.read_header = nuv_header,
.read_packet = nuv_packet,
+ .read_timestamp = nuv_read_dts,
.flags = AVFMT_GENERIC_INDEX,
};