The example encoder down-samples the input video frames a number of
times with a down-sampling factor, and then encodes and outputs
bitstreams with different resolutions.

Support arbitrary down-sampling factor, and down-sampling factor
can be different for each encoding level.

For example, the encoder can be tested as follows.
1. Configure with multi-resolution encoding enabled:
../libvpx/configure --target=x86-linux-gcc --disable-codecs
--enable-vp8 --enable-runtime_cpu_detect --enable-debug
--disable-install-docs --enable-error-concealment
--enable-multi-res-encoding
2. Run make
3. Encode:
If input video is 1280x720, run:
./vp8_multi_resolution_encoder 1280 720 input.yuv 1.ivf 2.ivf 3.ivf 1
(output: 1.ivf(1280x720); 2.ivf(640x360); 3.ivf(320x180).
The last parameter is set to 1/0 to show/not show PSNR.)
4. Decode:
./simple_decoder 1.ivf 1.yuv
./simple_decoder 2.ivf 2.yuv
./simple_decoder 3.ivf 3.yuv
5. View video:
mplayer 1.yuv -demuxer rawvideo -rawvideo w=1280:h=720 -loop 0 -fps 30
mplayer 2.yuv -demuxer rawvideo -rawvideo w=640:h=360 -loop 0 -fps 30
mplayer 3.yuv -demuxer rawvideo -rawvideo w=320:h=180 -loop 0 -fps 30

The encoding parameters can be modified in vp8_multi_resolution_encoder.c,
for example, target bitrate, frame rate...

Modified API. John helped a lot with that. Thanks!

Change-Id: I03be9a51167eddf94399f92d269599fb3f3d54f5

This value needs to be copied to each thread's data structure.
This fixed artifact problem in multi-thread encoder.

Change-Id: Iab6d9745a1d44846aa503184705376f63a505597

In Change I83202ffd, I deleted one too many lines.

Change-Id: If05d7c8988eb5c00898dc7c833ad7d99b5eb23e7

to the dqcoeff or qcoeff buffer.  The encoder would
populate the dc coeffs of the y blocks as a separate
stage (recon_dcblock) and the decoder would use a special
version of the idct.  This change eliminates the extra copy
and reduces the code footprint.

[Tero] Added needed changes to armv6 and NEON assembly.

Change-Id: I83202ffdbaf83f6e5dd69f4ba2519fcf0b13b3ba

API was not returning correct partition sizes on arm targets.
The armv5 token packing functions were not storing the information to the
partition size table.
As a fix, have one boolcoder instance allocated for each partition so
that partition sizes are internally available after all partitions
were encoded. This will also allow more flexibility in producing
several partitions in parallel.

Use buffer validation (overflow check) in all ARM bitpacking
functions.

Change-Id: I31c8a11d8a7613676f0ff50928cb2a2ab14fd169

Change-Id: Id3388985d754706b9fd1f079c47121e79a63efdf

Storing vp8_bilinear_filters_mmx in an mmx file and using it in an sse2
file is bad

Moving towards allowing --disable-mmx

Change-Id: I20493b35bdedcdcfc0915e6f05fdbe6c81a4a742

There was an implicit reference frame test order (typically LAST,
GOLD, ARF) in the mode selection logic, but this doesn't provide the
expected results when some reference frames are disabled. For
instance, in real-time mode, the speed selection logic often disables
the ARF modes. So if the user disables the LAST and GOLD frames, the
encoder was always choosing INTRA, when in reality searching the ARF
in this case has the same speed penalty as searching LAST would have
had.

Instead, introduce the notion of a reference frame search order. This
patch preserves the former priorities, so if a frame is disabled, the
other frames bump up a slot to take its place. This patch lays the
groundwork for doing something smarter in the frame test order, for
example considering temporal distance or looking at the frames used by
nearby blocks.

Change-Id: I1199149f8662a408537c653d2c021c7f1d29a700

Extend buffer write validation (overflow check) to single token
partition packing, both mb and row based functions.

Change-Id: I36e19b7d37fc43712d05c70e3ad223d3eb5b973d

Patch set 2: 64 bit build fix
Patch set 3: 64 bit crash fix

[Tero]
Patch set 4: Updated ARMv6 and NEON assembly.
             Added also minor NEON optimizations to subtract
             functions.

Patch set 5: x86 stride bug fix

Change-Id: I1fcca93e90c89b89ddc204e1c18f208682675c15

The calculated frame_rate is a state variable in the codec, and
shouldn't be maintained in the configuration struct. Move it to the
main part of cpi so that it isn't clobbered when the configuration
struct is updated. The initial framerate estimate is moved from the
vp8_cx_iface.c wrapper into the body of init_config() in onyx_if.c, so
that it is only called once and not reset on every call to
vp8_change_config().

Change-Id: I8d9a3d1283330d1ee297d07e9d78d1f2875f2465

Call the idct/add after the tokenize.  This is WIP with
the goal of creating a common idct/add for the encoder and
decoder. This move is necessary because the decoder's version
of the idct clobbers qcoeff, which is used by the tokenize.

Change-Id: I6b08d8e8397cd873647fa4fb9469884e3c876756

Added ARM optimized intra 4x4 prediction
 - 2x faster on Profiler compared to C-code compiled with -O3
 - Function interface changed a little to improve BLOCKD structure
   access

Change-Id: I9bc2b723155943fe0cf03dd9ca5f1760f7a81f54

The referenced function (SignalObjectAndWait) isn't used. Reduces the
warnings with mingw32-w64 which defines this.

Change-Id: I4ce592879ec9372bf196dac640204c4d370bd210

File not referenced from anywhere and no longer compiles.

Change-Id: I38b11bd60db615c2c2c9d7ad35caba3a1adf1750

vp8cx_mb_init_quantizer() needs to be called at least once to get
all values calculated. This change added one check to decide if
we could skip initialization or not.

Change-Id: I3f65eb548be57580a61444328336bc18c25c085b

Additional check of buffer level to ensure it doesn't exceed the
maximum buffer size.

Change-Id: I1ba4f8b09bbec89646885040ff47470196af521e

Added additional check of buffer level against maximum
buffer size.

Change-Id: Iaf1fbaf008601161e402b43ce82c3dbc129bf740

Added code to clip the buffer level to the maximum buffer
size. Without this the buffer level would increase
unchecked.

This bug was found when encoding an essentially static
scene at 2Mb/s. The encoder is unable to generate frames
consistent with the high data-rate because Q bottoms out
at Qmin.

As frames generated are consistently undersized the buffer
level increases and does not get checked against the
maximum size specified by the user (or default).

Change-Id: Id8a3c6323d3246da50f7cb53ddbf78b5528032c6

all of googletest import (0ab00a22) was marked executable

Change-Id: Id7b7ee03efc21ab998bb03349bd91644e8af25da

Fix compiler warning for passing a non const array
to a function expecting a const array by using an
intermediary pointer and casting.

Change-Id: I9bdd358ebdc926223993fb8fb2098ffedd2f3fc7

Updated eob changes to check_reset_2nd_coeffs function.

Change-Id: Id1b21c91c7f0fd286640b487ffe47867009b717d

Changed 'int eob' to 'char *eob' in BLOCKD so that both encoder and
decoder will use eobs[25] array from MACROBLOCKD structure. In future,
this will enable use of the decoder side IDCT in the encoder.

Change-Id: I6e1c011628cb8864fd4a0b80f0279ce16a5ca978

Adding support for several partitions within one input fragment.
This is necessary to fully support all possible packetization
combinations in the VP8 RTP profile. Several partitions can
be transmitted in the same packet, and they can only be split
by reading the partition lengths from the bitstream.

Change-Id: If7d7ea331cc78cb7efd74c4a976b720c9a655463

In some situations (f.g. error-resilient is turned on), vp8cx_mb
_init_quantizer() was called once per macroblock. Added checks
to avoid calculations when there is no change.

Change-Id: Ie4f0a5ade2202041254990a4e9d5b03bd1ac5aea

Prior to this fix, the clamping state of the last subblock partition
dominated, whereas the correct behavior is to clamp if any partition
needs clamping. This bug was introduced by v0.9.6-232-g6b25501

See also:
  [1]: http://code.google.com/p/webm/issues/detail?id=371
  [2]: https://bugzilla.mozilla.org/show_bug.cgi?id=696390

Change-Id: I444db492b4c4f05f039c7da6f4216da8207dc138

It is discovered that in rare situations the 2nd order block may
produce a few small magnitude coefficients that has no effect on
reconstruction. The situations are a combination of low quantizer
values (high quality) and low energy in residual signals (content
dependent). This commit added code to detect such cases and reset
the 2nd order block to all 0.

Patch 1 to 4 used code to do all-zero-check on idct result buffer,
and tests on derf set showed a consistent gain of .12%-.14% on all
metrics.But due to a recent change Ie31d90b, the idct result buffer
is not longer populated. So patch 5&6 use an alternative method to
detect the situations. Tests on derf set now shows a consistent
quality gain of .16%-.20%.

As suggested by Jim, Patch 7&8 removed the condition of all first
order block not having any coefficient, instead we reset 2nd order
coefficients to all 0 if sum of absolute value of the coefficients
is small. So it does slightly more than just detecting the oddity
as discussed above, but tests on derf set now show a consistent
gain of .20%-.23% on all metrics.

It is worth noting here that this change does not have any effect
on mid/high quantizer range, it only affects the quantizer value
18 or blow. Within this range, the change helps compression by up
to 2.5% on clips in the derf set.

Change-Id: I718e19cf59a4fc2462cb7070832759beb9f7e7dd

Tests showed ~1.2% performance boost on the HD clip used.
Performance will vary based on material.

Change-Id: Icbcf1a828750d5b4ae5252bf596b3ef594042e8a

Update ARM asm implementation of vp8_start_encode to new definition.

Change-Id: Ic44791c969e351082331ba6146c3384c01a0dfad

Small performance gains.

Change-Id: I709b9390a8a27a70f5f23574313b8db85ac7f23d

Interleaved vp8_find_near_mvs and vp8_mv_ref_probs.
2.5% to 4% performance improvement for the HD clips used.

Change-Id: Id888b667cf5ae2f0e19da18743140f055ff7de8d

The partial frame copy function used to copy an extra 8 lines above
and  below. The partial frame filtering can only modify 3 pixel rows
above the partial frame. Reduce copy to bare minimum needed, which is
4 lines, so that partial filtering on copied frame is possible.

Define the "magic" fraction number for partial filtering in
loopfilter.h .

Change-Id: I4791ffc541b6884b12759a0d0714a8faf16147ec

Restructure if statement to clarify the error condition. Trigger the
error before clobbering pc-> variables.

Change-Id: Id01cab798a341ce9899078fdcec265a0e942a0b7

Change-Id: I4fcd6e4656d9823aead941616cd63501aecbd6e2

Decode the mv mode with if-then-elses instead of traversing
the vp8_mv_ref_tree data structure.  This will make it
easier to interleave vp8_find_near_mvs and vp8_mv_ref_probs.

Change-Id: I1e798d6ec40fcaeeff06ccc82f81201978d12f74

into a function.

Change-Id: Ia023a0587100a52cb084f5d9d5512efa6198dad3

Prior size could be too small in some instances
resulting in an error.

Change-Id: Ic601e49cbae92c98a0e7fb51ba8c186b352ffba6

Did some cleanup as well.

Patchset 2:  Fixed bug.  Will revisit the segmentation logic.

Change-Id: Idf9fbcff9aaf467bdace9fbd58ef2cea6c602049

DETOK structure is not used anymore.

Change-Id: Id22e1af78fb85d4bb151237a60290d9364faf217

check to make sure that cx_data buffer has enough room before
writting to it, prior behavior did not which could result in a crash.

Change-Id: I3fab6f2bc4a96d7c675ea81acd39ece121738b28