This avoids having the compiler redundantly mask the values to
the smaller size.
Signed-off-by: NMans Rullgard <mans@mansr.com>

Signed-off-by: NMans Rullgard <mans@mansr.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: NMans Rullgard <mans@mansr.com>

Signed-off-by: NMans 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: NMans Rullgard <mans@mansr.com>

Signed-off-by: NMans Rullgard <mans@mansr.com>

Signed-off-by: NMans Rullgard <mans@mansr.com>

Signed-off-by: NMans Rullgard <mans@mansr.com>

Signed-off-by: NMans Rullgard <mans@mansr.com>

Signed-off-by: NMans Rullgard <mans@mansr.com>

Signed-off-by: NMans 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: NMans 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: NMans 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: NMans Rullgard <mans@mansr.com>

The 'shift' argument is always 1 so there is no need to pass it
explicitly in every call.
Signed-off-by: NMans Rullgard <mans@mansr.com>

The compiler performs this optimisation.
Signed-off-by: NMans 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: NMans Rullgard <mans@mansr.com>

Fixed-point audio codecs often use saturating arithmetic, and
special instructions for these operations are common.
Signed-off-by: NMans Rullgard <mans@mansr.com>

Signed-off-by: NDerek Buitenhuis <derek.buitenhuis@gmail.com>

Signed-off-by: NDerek Buitenhuis <derek.buitenhuis@gmail.com>

This is in preparation for adding support for other colorspaces
and coding types.
Signed-off-by: NDerek Buitenhuis <derek.buitenhuis@gmail.com>

If the dts difference is more than 1000 times the average dts
difference, restart the analysis.
Signed-off-by: NMartin Storsjö <martin@martin.st>

These are normally initialized to AV_NOPTS_VALUE at the start
of avformat_find_stream_info, but if a new stream is found while
this function is running (e.g. like in mpegts), the newly added
AVStreams didn't have these values properly initalized, leading
to avformat_find_stream_info terminating too soon (when the
first timestamps are far from 0).
Signed-off-by: NMartin Storsjö <martin@martin.st>

Some files' embedded art seems to have the mimetype 'image/JPG' instead
of 'image/jpg'. Libav fails to parse those because it matches
case-sensitively.

Use av_strncasecmp() to fix this behaviour.
Signed-off-by: NMohammad Alsaleh <msal@tormail.org>
Signed-off-by: NAnton Khirnov <anton@khirnov.net>

This fixes running FATE without --enable-gpl.

Signed-off-by: NMartin Storsjö <martin@martin.st>

Also fix the bytestream reader size parameter to take the
offset into account.
Signed-off-by: NMartin Storsjö <martin@martin.st>

They describe properties that are inherent to a codec (as described by
an AVCodecID) without referring to a specific implementation.

C++ does not allow to mix different enums, so e.g. code comparing
ACodecID with CodecID would fail to compile with gcc.

This very evil hack should fix this problem.

This makes struct AVDictionary fully opaque now that nothing
needs to access it directly any more.
Signed-off-by: NMans Rullgard <mans@mansr.com>

This adds a function to retrieve the number of entries in a
dictionary and updates the places directly accessing what should
be an opaque struct to use this new function instead.
Signed-off-by: NMans Rullgard <mans@mansr.com>

This addition must be done as 64-bit to avoid overflow and for
the subsequent clipping to be meaningful.
Signed-off-by: NMans Rullgard <mans@mansr.com>

In 16-bit arithmetic, x * 0xffffc is simply x * -4 with extra overflows,
(and the constant was probably meant to be 0xfffc).  Combined with the
shift, this simplifies to -x >> 1.  Finally, clearing the low two bits
with a 32-bit mask and switching to a 32-bit type allows more efficient
code on 32-bit machines.
Signed-off-by: NMans Rullgard <mans@mansr.com>

(x << 2) - x is just an optimisation of 3 * x the compiler is
perfectly capable of doing on its own.
Signed-off-by: NMans Rullgard <mans@mansr.com>