gecko/media/liboggz/key_frame_seek.patch
Chris Pearce c9119c8ceb Bug 463358. Support seeking to keyframes in liboggz. r=doublec
--HG--
extra : rebase_source : a8aa26fe569f1155936b496ecc35317d27a9aae7
2009-05-20 15:49:01 +12:00

162 lines
5.0 KiB
Diff

diff --git a/media/liboggz/include/oggz/oggz_seek.h b/media/liboggz/include/oggz/oggz_seek.h
--- a/media/liboggz/include/oggz/oggz_seek.h
+++ b/media/liboggz/include/oggz/oggz_seek.h
@@ -489,9 +489,22 @@ int oggz_set_data_start (OGGZ * oggz, og
* \retval -1 on failure (unit_target is not within range)
*/
ogg_int64_t
oggz_bounded_seek_set (OGGZ * oggz,
ogg_int64_t unit_target,
ogg_int64_t offset_begin,
ogg_int64_t offset_end);
+/**
+ * Seeks to the first key frame before unit_target, in the range
+ * [offset_begin, offset_end]. serial_nos contains an array of size serial_nos
+ * of serialnos of the streams which need to be seeked.
+ */
+ogg_int64_t
+oggz_keyframe_seek_set(OGGZ * oggz,
+ long* serial_nos,
+ int num_serialno,
+ ogg_int64_t unit_target,
+ ogg_int64_t offset_begin,
+ ogg_int64_t offset_end);
+
#endif /* __OGGZ_SEEK_H__ */
diff --git a/media/liboggz/src/liboggz/oggz_seek.c b/media/liboggz/src/liboggz/oggz_seek.c
--- a/media/liboggz/src/liboggz/oggz_seek.c
+++ b/media/liboggz/src/liboggz/oggz_seek.c
@@ -935,8 +935,131 @@ oggz_seek_byorder (OGGZ * oggz, void * t
long
oggz_seek_packets (OGGZ * oggz, long serialno, long packets, int whence)
{
return OGGZ_ERR_DISABLED;
}
#endif
+
+// Returns 1 if any of the elements of array |a|, which is of length |n|,
+// contain the value |val|. Otherwise returns 0.
+static int
+is_any(ogg_int64_t* a, int n, ogg_int64_t val)
+{
+ int i;
+ for (i=0; i<n; i++) {
+ if (a[i] == val) {
+ return 1;
+ }
+ }
+ return 0;
+}
+
+// Returns the index of the element in array |a|, which is of length |n|,
+// which contains the value |val|, or -1 of it's not present.
+static int
+find(long* a, int n, ogg_int64_t val)
+{
+ int i;
+ for (i=0; i<n; i++) {
+ if (a[i] == val) {
+ return i;
+ }
+ }
+ return -1;
+}
+
+// Returns the element with the smallest value in array |a|, which is
+// of length |n|.
+static ogg_int64_t
+minimum(ogg_int64_t* a, int n) {
+ ogg_int64_t m = 0x7FFFFFFFFFFFFFFF;
+ int i;
+ for (i=0; i<n; i++) {
+ if (a[i] < m) {
+ m = a[i];
+ }
+ }
+ return m;
+}
+
+ogg_int64_t
+oggz_keyframe_seek_set(OGGZ * oggz,
+ long* serial_nos,
+ int num_serialno,
+ ogg_int64_t unit_target,
+ ogg_int64_t offset_begin,
+ ogg_int64_t offset_end)
+{
+ oggz_off_t offset_at;
+ oggz_off_t offset_next;
+ ogg_int64_t granule_at;
+ ogg_int64_t unit_at;
+ ogg_int64_t key_granule_at, key_unit_at;
+ long serialno;
+ ogg_page * og;
+ int granule_shift = 0, idx;
+ ogg_int64_t* key_frames = 0;
+
+ unit_at = oggz_bounded_seek_set(oggz,
+ unit_target,
+ offset_begin,
+ offset_end);
+ // Time isn't in the specified offset range, fail.
+ if (unit_at == -1)
+ return -1;
+
+ // We've seeked to beginning, we're at a key frame.
+ if (unit_at == 0)
+ return 0;
+
+ // Backup this, in case we need to fail.
+ offset_at = oggz->offset;
+
+ key_frames = oggz_malloc(sizeof(ogg_int64_t) * num_serialno);
+ if (!key_frames) {
+ // Malloc failure. We can still exit with the seek finishing at a non
+ // key frame.
+ return unit_at;
+ }
+ memset(key_frames, -1, sizeof(ogg_int64_t) * num_serialno);
+
+ // Find the key frame offset for every stream.
+ og = &oggz->current_page;
+ while (is_any(key_frames, num_serialno, -1)) {
+ do {
+ offset_next = oggz_get_prev_start_page (oggz, og, &granule_at, &serialno);
+ if (offset_next <= 0 || granule_at == 0) {
+ // At beginning of file, or some other failure. Return with
+ // non-key frame seek if possible.
+ oggz_free(key_frames);
+ offset_at = oggz_reset (oggz, offset_at, unit_at, SEEK_SET);
+ return (offset_at == -1) ? -1 : unit_at;
+ }
+ } while (granule_at < 0);
+
+ idx = find(serial_nos, num_serialno, serialno);
+ if (idx == -1 || key_frames[idx] != -1)
+ continue;
+
+ granule_shift = oggz_get_granuleshift(oggz, serialno);
+ key_granule_at = (granule_at >> granule_shift) << granule_shift;
+ key_unit_at = oggz_get_unit(oggz, serialno, key_granule_at);
+
+ if (key_unit_at < unit_target)
+ key_frames[idx] = key_unit_at;
+ }
+
+ // Seek to 100ms before the earliest of all the streams' key frames.
+ // This is so that after the seek, the decoder will defintately return frames
+ // at or before get the key frame. Without this, some decoders will return
+ // frames which start after the specified time - after the key frame.
+ key_unit_at = minimum(key_frames, num_serialno);
+ unit_at = oggz_bounded_seek_set(oggz,
+ MAX((key_unit_at - 100), 0),
+ offset_begin,
+ offset_end);
+ oggz_free(key_frames);
+
+ return unit_at;
+}