replaygain: fix gain sign decoding

The gain sign was incorrectly decoded: since the FFSIGN() macro treats 0 as
negative, gain values starting with "0." were always decoded as negative.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
replaygain: correctly parse peak values

According to the ReplayGain spec, the peak amplitude may overflow and may result
in peak amplitude values greater than 1.0 with psychoacoustically coded audio,
such as MP3. Fully compliant decoders must allow peak overflows.

Additionally, having peak values in the 0<->UINT32_MAX scale makes it more
difficult for applications to actually use the peak values (e.g. when
implementing clipping prevention) since values have to be rescaled down.

This patch corrects the peak parsing by removing the rescaling of the decoded
values between 0 and UINT32_MAX and the 1.0 upper limit.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
flacdec: export replaygain tags from Vorbis comments

Signed-off-by: Anton Khirnov <anton@khirnov.net>
oggparsevorbis: export replaygain tags from Vorbis comments

Signed-off-by: Anton Khirnov <anton@khirnov.net>
replaygain: remove unused variable

Signed-off-by: Anton Khirnov <anton@khirnov.net>
x86/synth_filter: add synth_filter_sse

Build only on x86_32 targets.

Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
x86/synth_filter: add synth_filter_avx

Sandy Bridge Win64:
180 cycles in ff_synth_filter_inner_sse2
150 cycles in ff_synth_filter_inner_avx

Also switch some instructions to a three operand format to avoid
assembly errors with Yasm 1.1.0 or older.

Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
x86/synth_filter: add synth_filter_fma3

Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>