2012-05-10 v1.1.0 "Eider"
This introduces a number of enhancements, mostly focused on real-time
encoding. In addition, it fixes a decoder bug (first introduced in
Duclair) so all users of that release are encouraged to upgrade.
- Upgrading:
This release is ABI and API compatible with Duclair (v1.0.0). Users
of older releases should refer to the Upgrading notes in this
document for that release.
This release introduces a new temporal denoiser, controlled by the
VP8E_SET_NOISE_SENSITIVITY control. The temporal denoiser does not
currently take a strength parameter, so the control is effectively
a boolean - zero (off) or non-zero (on). For compatibility with
existing applications, the values accepted are the same as those
for the spatial denoiser (0-6). The temporal denoiser is enabled
by default, and the older spatial denoiser may be restored by
configuring with --disable-temporal-denoising. The temporal denoiser
is more computationally intensive than the spatial one.
This release removes support for a legacy, decode only API that was
supported, but deprecated, at the initial release of libvpx
(v0.9.0). This is not expected to have any impact. If you are
impacted, you can apply a reversion to commit 2bf8fb58 locally.
Please update to the latest libvpx API if you are affected.
- Enhancements:
Adds a motion compensated temporal denoiser to the encoder, which
gives higher quality than the older spatial denoiser. (See above
for notes on upgrading).
In addition, support for new compilers and platforms were added,
including:
improved support for XCode
Android x86 NDK build
OS/2 support
SunCC support
Changing resolution with vpx_codec_enc_config_set() is now
supported. Previously, reinitializing the codec was required to
change the input resolution.
The vpxenc application has initial support for producing multiple
encodes from the same input in one call. Resizing is not yet
supported, but varying other codec parameters is. Use -- to
delineate output streams. Options persist from one stream to the
next.
Also, the vpxenc application will now use a keyframe interval of
5 seconds by default. Use the --kf-max-dist option to override.
- Speed:
Decoder performance improved 2.5% versus Duclair. Encoder speed is
consistent with Duclair for most material. Two pass encoding of
slideshow-like material will see significant improvements.
Large realtime encoding speed gains at a small quality expense are
possible by configuring the on-the-fly bitpacking experiment with
--enable-onthefly-bitpacking. Realtime encoder can be up to 13%
faster (ARM) depending on the number of threads and bitrate
settings. This technique sees constant gain over the 5-16 speed
range. For VC style input the loss seen is up to 0.2dB. See commit
52cf4dca for further details.
- Quality:
On the whole, quality is consistent with the Duclair release. Some
tweaks:
Reduced blockiness in easy sections by applying a penalty to
intra modes.
Improved quality of static sections (like slideshows) with
two pass encoding.
Improved keyframe sizing with multiple temporal layers
- Bug Fixes:
Corrected alt-ref contribution to frame rate for visible updates
to the alt-ref buffer. This affected applications making manual
usage of the frame reference flags, or temporal layers.
Additional constraints were added to disable multi-frame quality
enhancement (MFQE) in sections of the frame where there is motion.
(#392)
Fixed corruption issues when vpx_codec_enc_config_set() was called
with spatial resampling enabled.
Fixed a decoder error introduced in Duclair where the segmentation
map was not being reinitialized on keyframes (#378)