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author | Attila Nagy <attilanagy@google.com> | 2012-02-09 12:37:03 +0200 |
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committer | Yunqing Wang <yunqingwang@google.com> | 2012-02-29 12:13:37 -0500 |
commit | 52cf4dcaea10f97d25d8a3585704a1e47b384751 (patch) | |
tree | 6fb5acff2e02f2e153e206284f5075ebce548674 /vp8/common/coefupdateprobs.h | |
parent | ce328b855f951e5a9fd0d9d92df09d65ea0d8be9 (diff) | |
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Packing bitstream on-the-fly with delayed context updates
Produce the token partitions on-the-fly, while processing each MB.
Context is updated at the beginning of each frame based on the
previoud frame's counters. Optimally encoder outputs partitions in
separate buffers. For frame based output, partitions are concatenated
internally.
Limitations:
- enabled just in combination with realtime-only mode
- number of encoding threads has to be equal or less than the
number of token partitions. For this reason, by default the encoder
will do 8 token partitions.
- vpxenc supports partition output (-P) just in combination with
IVF output format (--ivf)
Performance:
- Realtime encoder can be up to 13% faster (ARM) depending on the number
of threads and bitrate settings. Constant gain over the 5-16 speed
range.
- Token buffer reduced from one frame to 8 MBs
Quality:
- quality is affected by the delayed context updates. This again
dependents on input material, speed and bitrate settings. For VC
style input the loss seen is up to 0.2dB. If error-resilient=2
mode is used than the effect of this change is negligible.
Example:
./configure --enable-realtime-only --enable-onthefly-bitpacking
./vpxenc --rt --end-usage=1 --fps=30000/1000 -w 640 -h 480
--target-bitrate=1000 --token-parts=3 --static-thresh=2000
--ivf -P -t 4 -o strm.ivf tanya_640x480.yuv
Change-Id: I127295cb85b835fc287e1c0201a67e378d025d76
Diffstat (limited to 'vp8/common/coefupdateprobs.h')
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