Yaowu Xu [Mon, 6 Dec 2010 21:33:01 +0000 (13:33 -0800)]
adjust RDMULT for UV plane in quantization RDO
This patch adds a weighting factor on RDMULT for UV blocks. The change
has an overall gain about 0.5% based on ssim, between 0.1 and 0.2% by
psnr numbers.
Scott LaVarnway [Mon, 6 Dec 2010 21:42:52 +0000 (16:42 -0500)]
vp8_rd_pick_best_mbsegmentation code restructure
Moved the code from the segmentation loop into a function
which is now called for each segment. This will allow us
to change the segment order checking more easily.
Paul Wilkins [Sat, 4 Dec 2010 10:04:12 +0000 (10:04 +0000)]
Change to inter_minq table.
The inter_minq table controls the range of quantizers available
for a particular frame in two pass relative to a max Q value.
The changes reduces the range somewhat. The effect of this
was a small increase (0.3% average) in psnr for the test set
but it should also help encode speed somewhat for higher
quality modes as it will reduce the number of iterations in the
recode loop.
The change damps the range of quantizers available locally
within a section of a clip and should therefore help keep quality
more uniform. If there is systematic overshoot or undershoot the
range can shift gradually to accommodate. However, there is
some increased risk of overshoot or undershoot against the target
bit rate in VBR mode and this risk will be more pronounced for short
clips.
The change damps the range of quantizers available locally
within a section of a clip and should therefore help keep quality
more uniform. If there is systematic overshoot or undershoot the
range can shift gradually to accommodate. However, there is
some increased risk of overshoot or undershoot against the
target bit rate in VBR mode and this risk will be more
pronounced for short clips.
Yunqing Wang [Fri, 3 Dec 2010 16:26:21 +0000 (11:26 -0500)]
Improve MV prediction accuracy to achieve performance gain
Add vp8_mv_pred() to better predict starting MV for NEWMV
mode in vp8_rd_pick_inter_mode(). Set different search
ranges according to MV prediction accuracy, which improves
encoder performance without hurting the quality. Also,
as Yaowu suggested, using diamond search result as full
search starting point and therefore adjusting(reducing)
full search range helps the performance.
Fritz Koenig [Thu, 18 Nov 2010 18:40:58 +0000 (10:40 -0800)]
Set refresh_alt_ref_frame on keyframe encode.
On a keyframe alt ref and golden are refreshed. The flag was
not being set and so on the frame after a keyframe, motion
search would occur on the alt ref frame. This is not necessary
because the alt ref frame identical to the last frame in this
scenario.
Handle corner case where a forward alt-ref frame is put
directly after a keyframe.
Pascal Massimino [Wed, 24 Nov 2010 08:22:59 +0000 (00:22 -0800)]
allow dimensions as low as 1 pixel
remove warning comment in vpxenc.c: in case of 1x1 picture,
detect_bytes will be equal to '3' and we'll fall back to
RAW_TYPE.
fix read_frame() by tracking the pre-read buffer length
in the struct detect
Paul Wilkins [Mon, 22 Nov 2010 13:17:35 +0000 (13:17 +0000)]
Recalibration of bits per MB tables
The baseline bits per MB prediction tables have been
re calibrated based on the assumption that bits per mb
is inversely proportional to the quantizer level.
Yaowu Xu [Mon, 1 Nov 2010 21:04:01 +0000 (14:04 -0700)]
remove low pass filtering from two 4x4 intra prediction
In the process of developing new intra prediction modes, tests have
shown removal of the low pass filtering from B_HE_PRED and B_VE_PRED
has an overall minor positive impact in both PSNR and SSIM metric.
Overall difference is about 0.1%. The change shall also have a small
positive impact on speed. Intuitively, this change should also reduce
some of the tendency of "flattening"
Yaowu Xu [Thu, 18 Nov 2010 17:10:30 +0000 (09:10 -0800)]
changed MAX_PSNR to 100
Changing the MAX_PSNR to 100 to allow testing of further experiments
on extending quantizer range to near lossless. With an effective
quantizer of 1, encoder achieves ~68DB, which is consistent with
fdct/idct round trip error.
Yaowu Xu [Tue, 16 Nov 2010 21:58:21 +0000 (13:58 -0800)]
extends the range of tokens
Extending the value range of tokens allows further experiments on
extending quantizer range. Encoder and decoder were verified to
produce matching reconstructed buffers by tests with forced
quantized value of 1.
Paul Wilkins [Wed, 17 Nov 2010 15:12:04 +0000 (15:12 +0000)]
Replaced recode loop test with a function call
Replaced existing code to decide if a frame recode is required
with a function call. This is to simplify addition of extra clauses
that may be needed for the planned constrained quality mode.
Also fixed a bug where by alt ref not considered in the test.
John Koleszar [Wed, 17 Nov 2010 14:13:54 +0000 (09:13 -0500)]
vp8mt_alloc_temp_buffers: make prototype return void
This function was never called in a context expecting a return value,
the return value was always a constant, and the !CONFIG_MULTITHREAD
path didn't have a return statement, which caused a compiler warning.
This patch changes the function to return void instead.
Paul Wilkins [Mon, 15 Nov 2010 17:47:12 +0000 (17:47 +0000)]
Bad cost tables used in ARNR filtering.
The use of incorrect mv costing tables in the ARNR sub-pel
filtering code led to corruption of the altref buffer in some cases,
particularly at low data rates.
The average gain from this fix is about 0.3% but there are a few
extreme cases where nasty and visible artifacts manifested and
for these few data points the improvement is > 10%.
Frank Galligan [Thu, 4 Nov 2010 03:33:00 +0000 (23:33 -0400)]
Fixed bug first cluster timecode of webm file is wrong.
When the first pts equaled 0 ivfenc was incorrectly increasing the
pts by 1. I changed the pts and last pts to be signed. I also set
the default value of last pts to -1.
Yaowu Xu [Thu, 11 Nov 2010 05:16:17 +0000 (21:16 -0800)]
make rdmult adaptive for intra in quantizer RDO
This intends to correct the tendency that VP8 aggressively favors rate
on intra coded frames. Experiments tested different numbers in [0, 1]
and found 9/16 overall provided about 2-4% gains for all-intra coded
clips based on vpx-ssim metric. The impact on regular encoded clips
is much smaller but positive overall. Overall impact on psnr is also
positive even though very small.
John Koleszar [Thu, 11 Nov 2010 17:41:07 +0000 (12:41 -0500)]
quantizer: fix assertion in fast quantizer path
The fast quantizer assembly code has not been updated to match the new
exact quantizer, which was made the default in commit 6adbe09.
Specifically, they are not aware of the potential for the coefficient
to be scaled, which results in the quantized result exceeding the range
of the DCT. This patch restores the previous behavior of using the
non-shifted coefficients when in the fast quantizer code path, but
unfortunately requires rebuilding the tables when switching between the
two.
Use of temporal context for encoding delta updates.
- 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.
projects / libvpx / log