[x264-devel] x264 Development Newsletter: Vol 12

[Jason Garrett-Glaser]

This is the twelfth x264 development newsletter.  If you missed the
first eleven, this is a regular email containing updates on fixes and
improvements in the most recent x264 push, along with updates on
what's coming next.  Previous versions can be found in the mailing
list archives.

Fixes:

Fix some Intel compiler warnings.

Fix a crash in the mp4 muxer in x264cli if x264_encoder_open failed.

Fix a case in which a malloc(0) was done; on some OSs, like Solaris,
this returned a null pointer instead of a pointer to a 0-byte memory
block, thus causing libx264 to think that its malloc failed.  Both
these behaviors are POSIX-compatible.

Fix a minor bug in RD caused by a stray semicolon.  It probably didn't
affect much.

Fix a memory leak on encoder close if not all frames were flushed
during encoding.

Improvements:

Save memory: don't init MV cost data that isn't needed.

Use bs_write1 for all 1-bit header bits, not just some.

Even more accurate handling of slice-max-size escape bytes: track the
actual bytes rather than trying to estimate them.  Slightly slower,
but should cover even the most insane corner cases (we found a corner
case in which x264 could literally end up outputting one escape byte
for every single macroblock!).

In frame-packing 3D, don't place scenecuts on the right view, ever.
Some players dislike this.  Note: x264 won't stop you from using an
odd keyint, which will mess this up.

The first edition of Daniel Kang's massive AVX patch is in --
hopefully this will give a few % of performance on the new Sandy
Bridge chips.

Upcoming:

--device and automatic --level restriction support is in the works, as
part of Google Code-In.  The patch is done, but needs review.

A per-option help system is in the works, as part of Google Code-In.
The patch is done, but needs editing of the help entries.

Adaptive MBAFF development is actually coming along for once this
time.  Inter frames are basically done.

x262 is under development: a best-in-class MPEG-2 encoder built using
the x264 framework.  P-frames are done and working.

Work is planned to integrate x264 with the Sandy Bridge's encoding
ASIC for improved encoding performance.  Current status is: waiting on
Intel (these guys move at the speed of an obese one-legged paraplegic
three-toed sloth swimming down a river of frozen helium while chained
to an osmium anchor stuck inside a black hole).

Jason Garrett-Glaser

The x264 Team