- Used three probability approach for temporal context as follows:
P0 - probability of no change if both above and left not changed
P1 - probability of no change if one of above and left has changed
P2 - probability of no change if both above and left have changed
In addition, a 1 bit/frame has been used to decide whether to use temporal context or to encode directly. The cost of using both the schemes is calculated ahead and the temporal_update flag is set if the cost of using temporal context is lower than encoding the segment ids directly.
This approach has given around 20% reduction in cost of bits needed to encode segmentation ids.
Change-Id: I44a5509599eded215ae5be9554314280d3d35405
Loopfilter deltas are initialized to zero on keyframes in the decoder.
The values then persist from the previous frame unless an update bit
is set in the bitstream. This data is not included in the entropy
data saved by the 'refresh entropy' bit in the bitstream, so it is
effectively an additional contextual element beyond the 3 ref-frames
and the entropy data.
The encoder was treating this delta update bit as update-if-nonzero,
meaning that the value would be refreshed even if it hadn't changed,
and more significantly, if the correct value for the delta changed
to zero, the update wouldn't be sent, and the decoder would preserve
the last (presumably non-zero) value.
This patch updates the encoder to send an update only if the value
has changed from the previously transmitted value. It also forces the
value to be transmitted in error resilient mode, to account for lost
context in the event of lost frames.
Change-Id: I56671d5b42965d0166ac226765dbfce3e5301868
Modified code so that:
-When above and left contexts are same and not equal to current segment id, it needs to read a maximum of 2 segment_tree_probabilities.
- When above and left contexts are different and not equal to current segment id, it needs to read only a single segment_tree_probability.
Change-Id: Idc2cf2c4afcc6179b8162ac5a32c948ff5a9a2ba
-Updates by making use of spatial correlation.
-Checks if the segment_id is same as above or left context and encodes only the update to the map instead of updating individual segment_ids.
Change-Id: Ib861df97e8aa2b37516219eeddcdbaf552b6a249
Changes 'The VP8 project' to 'The WebM project', for consistency
with other webmproject.org repositories.
Fixes issue #97.
Change-Id: I37c13ed5fbdb9d334ceef71c6350e9febed9bbba
Moved partition_bmi and partition_count out of MB_MODE_INFO and
placed into MACROBLOCK. Also reduced the size of other members
of the MB_MODE_INFO struct. For 1080p, the memory was reduced
by 1,209,516 bytes. The decoder performance appeared to improve
by 3% for the clip used.
Note: The main goal for this change is to improve the decoder
performance. The encoder will be revisited at a later date for
further structure cleanup.
Change-Id: I4733621292ee9cc3fffa4046cb3fd4d99bd14613
The mv_ref and sub_mv_ref token encodings are indexed from NEARESTMV
and LEFT4X4, respectively, rather than being zero-based like the
other token encodings.
Change-Id: I3699c3f84111209ecfb91097c4b900773e9a3ad5
When the license headers were updated, they accidentally contained
trailing whitespace, so unfortunately we have to touch all the files
again.
Change-Id: I236c05fade06589e417179c0444cb39b09e4200d
