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| author |   Sam James <sam@gentoo.org> | 2022-12-11 16:53:02 +0000 |
|---|---|---|
| committer | Sam James <sam@gentoo.org> | 2022-12-11 16:53:02 +0000 |
| commit | 2c433ff21fe5beda9c28986c33ad8b5bdb869352 (patch) | |
| tree | 678ec40f9458a18080eaa2d61975b61459e08b53 /media-video/ffmpeg/metadata.xml | |
| parent | kde-apps/kdenetwork-filesharing: fix build w/ gcc 13 (diff) | |
| download | gentoo-2c433ff21fe5beda9c28986c33ad8b5bdb869352.tar.gz gentoo-2c433ff21fe5beda9c28986c33ad8b5bdb869352.tar.bz2 gentoo-2c433ff21fe5beda9c28986c33ad8b5bdb869352.zip | |
media-video/ffmpeg: add explanation of USE=hardcoded-tables
This mostly quotes https://trac.ffmpeg.org/wiki/CompilationGuide ("Performance Tips").
Signed-off-by: Sam James <sam@gentoo.org>
Diffstat (limited to 'media-video/ffmpeg/metadata.xml')
| -rw-r--r-- | media-video/ffmpeg/metadata.xml | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/media-video/ffmpeg/metadata.xml b/media-video/ffmpeg/metadata.xml index 60511928e367..54cb9b3546d3 100644 --- a/media-video/ffmpeg/metadata.xml +++ b/media-video/ffmpeg/metadata.xml @@ -25,7 +25,16 @@ <flag name="gcrypt">Enables gcrypt support: Needed for rtmp(t)e support if openssl, librtmp or gmp is not used.</flag> <flag name="gme">Enables support for <pkg>media-libs/game-music-emu</pkg> for playing various video game music formats.</flag> <flag name="gpl">Build GPL code. Should be enabled unless you require LGPL binaries.</flag> - <flag name="hardcoded-tables">Use pre-calculated tables rather than calculating them on the fly.</flag> + <flag name="hardcoded-tables"> + Use pre-calculated tables rather than calculating them on the fly. + + It results in an increase of approximately 15% in the size of libavcodec, the main library impacted by this change. + It enables savings in table generation time, done once at codec initialization, since by hardcoding the tables, + they do not need to be computed at runtime. However, the savings are often negligible (~100k cycles is a typical number) especially when amortized + over the entire encoding/decoding operation. + + Improvements are being made to the runtime initialization, and so over time, this option will have an impact on fewer and fewer codecs. + </flag> <flag name="iec61883"> Support for FireWire DV/HDV input device using <pkg>media-libs/libiec61883</pkg>.</flag> <flag name="jpegxl">Enable JPEG XL de/encoding via <pkg>media-libs/libjxl</pkg>.</flag> <flag name="kvazaar">Enables <pkg>media-libs/kvazaar</pkg> based HEVC encoder.</flag> |