flacdec: do not overwrite a channel layout set by the caller

The channel layout mask for non-standard layouts is typically stored at
the container level (as a vorbiscomment tag) for FLAC.
flac demuxer: parse the WAVEFORMATEXTENSIBLE_CHANNEL_MASK tag

It is used to store the channel mask for non-standard layouts.
flac muxer: write WAVEFORMATEXTENSIBLE_CHANNEL_MASK tag for multichannel files
flac: make avpriv_flac_parse_block_header() inline

This avoids all the ABI troubles associated with avpriv_.
Since this function is very small and does not depend on any tables,
making it inline should have no adverse effects.
matroskadec: split parsing tracks into a separate function
matroskadec: export just the STREAMINFO block as FLAC extradata

It contains all information that is used by the decoder and the other
FLAC-capable demuxers (flacdec, ogg) export only STREAMINFO as well.
matroskadec: parse the channel layout mask for FLAC

It is commonly stored in a vorbiscomment block in codec private data.
vorbiscomment: simplify API by using av_dict_count()
matroskaenc: write the channel mask for FLAC
ppc: util_altivec: Drop unused macros
ppc: Move vec_unaligned_load macro to util_altivec

This allows reusing it from multiple files.
oggenc: Fix the EOS flag

This corrects the bug that caused the checksums to change in
9767d7c092c890ecc5953452e8a951fd902dd67b.

It caused the EOS flag to be set incorrectly; the ogg spec does not
allow it to be set in the middle of a logical bitstream.

Signed-off-by: Andrew Kelley <superjoe30@gmail.com>
Signed-off-by: Martin Storsjö <martin@martin.st>
avformat: Provide a standard compliance flag

Provide f_strict for avconv usage.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
nut: Support experimental NUT 4 features

Add the low overhead pipe mode and the extended broadcast mode.
Export the options as 'syncponts' since it impacts only that.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
avresample: Add avresample_get_out_samples

Utility function to get the upper bound on the number of samples the
resampler would output.
af_resample: Use avresample_get_out_samples