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Martin Storsjö
402546a172
The idct32x32 function actually pushed q4-q7 onto the stack even though it didn't clobber them; there are plenty of registers that can be used to allow keeping all the idct coefficients in registers without having to reload different subsets of them at different stages in the transform. Since the idct16 core transform avoids clobbering q4-q7 (but clobbers q2-q3 instead, to avoid needing to back up and restore q4-q7 at all in the idct16 function), and the lanewise vmul needs a register in the q0-q3 range, we move the stored coefficients from q2-q3 into q4-q5 while doing idct16. While keeping these coefficients in registers, we still can skip pushing q7. Before: Cortex A7 A8 A9 A53 vp9_inv_dct_dct_32x32_sub32_add_neon: 18553.8 17182.7 14303.3 12089.7 After: vp9_inv_dct_dct_32x32_sub32_add_neon: 18470.3 16717.7 14173.6 11860.8 Signed-off-by: Martin Storsjö <martin@martin.st>
Libav
Libav is a collection of libraries and tools to process multimedia content such as audio, video, subtitles and related metadata.
Libraries
libavcodecprovides implementation of a wider range of codecs.libavformatimplements streaming protocols, container formats and basic I/O access.libavutilincludes hashers, decompressors and miscellaneous utility functions.libavfilterprovides a mean to alter decoded Audio and Video through chain of filters.libavdeviceprovides an abstraction to access capture and playback devices.libavresampleimplements audio mixing and resampling routines.libswscaleimplements color conversion and scaling routines.
Tools
- avconv is a command line toolbox to manipulate, convert and stream multimedia content.
- avplay is a minimalistic multimedia player.
- avprobe is a simple analisys tool to inspect multimedia content.
- Additional small tools such as
aviocat,ismindexandqt-faststart.
Documentation
The offline documentation is available in the doc/ directory.
The online documentation is available in the main website and in the wiki.
Examples
Conding examples are available in the doc/example directory.
License
Libav codebase is mainly LGPL-licensed with optional components licensed under GPL. Please refer to the LICENSE file for detailed information.