[Bug 383240] [NEW] Integrate and enable ARMv5TE/v6/VFP and NEON optimisations from ffmpeg trunk for armel

[Dave Martin]

Public bug reported:

Binary package hint: ffmpeg

Since quite a lot of ARM architecture optimisations are now integrated
in the ffmpeg trunk, ideally Ubuntu should enable them for Karmic
onwards.

The related changes have been committed to the ffmpeg trunk at
svn://svn.ffmpeg.org/ffmpeg/trunk from 2008-08-25 onwards; however, most
of the support is newer than this.  Some support was present in the
source used for Jaunty, but it was not enabled (no run-time detection
was implemented, and the NEON code was statically disabled with
configure --disable-neon).

Måns Rullgård (the ffmpeg trunk developer who did the optimisations) is
concerned that the hwcaps information provided by the kernel to
userspace is not really sufficient for runtime processor feature
detection, and is looking at ways of providing more detailed capability
information to userspace.

However, this support is speculative at present, and is unlikely to be
merged in all the right places in time for Karmic, so we may need a
simpler approach, whether it's based on run-time hwcaps checks in
libavcodec, or using multiple library build passes and the hwcaps-based
shared library selection in libc, or something else.


ffmpeg also contains some VFP, armv5te and armv6 optimisations. Based on the v6+VFP baseline for Karmic, I suggest that these can be turned on statically, when the karmic toolchain has stabilised sufficiently.

** Affects: ffmpeg (Ubuntu)
     Importance: Undecided
     Assignee: Canonical Mobile Team (canonical-mobile)
         Status: New

** Affects: ffmpeg (Ubuntu Karmic)
     Importance: Undecided
     Assignee: Canonical Mobile Team (canonical-mobile)
         Status: New

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Integrate and enable ARMv5TE/v6/VFP and NEON optimisations from ffmpeg trunk for armel
https://bugs.launchpad.net/bugs/383240
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