There are several reasons for doing that:
1. It documents the code for the reader and helps find
inconsistencies and bugs.
2. For rej_perms, it guarantees the change will be done
even if the output reference can be created by several
code paths.
3. It can be used to predict cases where a copy will,
or will not happen and optimize buffer allocation
(for example not request a rare direct-rendering buffer
from a device sink if it will be copied anyway).
Note that a filter is still allowed to manage the permissions
on its own without using these fields.
The resolution is in the packets, so decoding must happen.
Since most other formats do not set the dimension, make it
a special case for PGS. If other codecs were to have the
same requirement, using a CODEC_CAP would be preferred.
DVD subtitles packets can only encode a single rectangle:
if there are several, copy them into a big transparent one.
DVD subtitles rely on an external 16-colors palette:
use a reasonable default one, stored in the private context,
and encode it into the extradata, as specified by Matroska.
TODO: allow to change the palette with an option.
Each packet can use four colors out of the global palette.
The old logic was to map transparent colors to the color 0
and all other colors to 3, 2, 1, cyclically in descending
frequency order, completely disregarding the original color.
Select the "best" four colors from the global palette, according
to heuristics based on frequency, opacity and brightness, and
arrange them in standard DVD order: background, foreground,
outline, other.
TODO: select the alpha value more finely; see if CHG_COLCON can
allow more than 4 colors per packet.
Reference:
http://dvd.sourceforge.net/dvdinfo/spu.html
With these changes, dvdsubenc can be used to transcode DVB subtitles
and get a very decent result.
Note that the symbols used to run the hardware decoder in asynchronous mode
has been marked as deprecated and will be dropped at a future version dump.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
many branches and cases of scale_vector are irrelevant for the case here
and by inlining they can be reliably removed.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
It appears someone thinks this special case can be reached
Well, it cannot, thus not only do we not need to optimize it
we dont need it at all
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
* qatar/master: (22 commits)
g723.1: do not pass large structs by value
g723.1: do not bounce intermediate values via memory
g723.1: declare a variable in the block it is used
g723.1: avoid saving/restoring excitation
g723.1: avoid unnecessary memcpy() in residual_interp()
g723.1: make postfilter write directly to output buffer
g723.1: drop unnecessary variable buf_ptr in formant_postfilter()
g723.1: make scale_vector() output to a separate buffer
g723.1: make autocorr_max() work on an arbitrary buffer
g723.1: do not needlessly use int64_t
g723.1: use saturating addition functions
g723.1: optimise scale_vector()
g723.1: remove useless uses of MUL64()
g723.1: remove unnecessary argument 'shift' from dot_product()
g723.1: deobfuscate "(x << 4) - x" to "15 * x"
celp: optimise ff_celp_lp_synthesis_filter()
libavutil: add saturating addition functions
cllc: Implement ARGB support
cllc: Add support for QRGB
cllc: Rename some funcs to represent what they actually do
...
Conflicts:
LICENSE
libavcodec/g723_1.c
libavcodec/x86/Makefile
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Allow to select specific documentation components, and reliably check for
component dependencies.
In particular, check for perl presence on the system.
This is a port of the MPlayer hue filter (libmpcodecs/vf_hue.c) by
Michael Niedermayer.
Signed-off-by: Jérémy Tran <tran.jeremy.av@gmail.com>
Signed-off-by: Stefano Sabatini <stefasab@gmail.com>
Although a reasonable compiler will probably optimise out the
actual store and load, this operation still implies a truncation
to 16 bits which the compiler will probably not realise is not
necessary here.
Signed-off-by: Mans Rullgard <mans@mansr.com>
Writing the scaled excitation to a scratch buffer (borrowing the
'audio' array) instead of modifying it in place avoids the need
to save and restore the unscaled values.
Signed-off-by: Mans Rullgard <mans@mansr.com>
Use saturating addition functions instead of 64-bit intermediates
and separate clipping. This is much faster when dedicated
instructions are available.
Signed-off-by: Mans Rullgard <mans@mansr.com>
Firstly, nothing in this function can overflow 32 bits so the use
of a 64-bit type is completely unnecessary. Secondly, the scale
is either a power of two or 0x7fff. Doing separate loops for these
cases avoids using multiplications. Finally, since only the number
of bits, not the actual value, of the maximum value is needed, the
bitwise or of all the values serves the purpose while being faster.
It is worth noting that even if overflow could happen, it was not
handled correctly anyway.
Signed-off-by: Mans Rullgard <mans@mansr.com>
The operands in both cases are 16-bit so cannot overflow a 32-bit
destination. In gain_scale() the inputs are reduced to 14-bit,
so even the shift cannot overflow.
Signed-off-by: Mans Rullgard <mans@mansr.com>
Adding instead of subtracting the products in the loop allows the
compiler to generate more efficient multiply-accumulate instructions
when 16-bit multiply-subtract is not available. ARM has only
multiply-accumulate for 16-bit operands. In general, if only one
variant exists, it is usually accumulate rather than subtract.
In the same spirit, using the dedicated saturation function enables
use of any special optimised versions of this.
Signed-off-by: Mans Rullgard <mans@mansr.com>
Fixed-point audio codecs often use saturating arithmetic, and
special instructions for these operations are common.
Signed-off-by: Mans Rullgard <mans@mansr.com>
