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| author | Justin Ruggles <justin.ruggles@gmail.com> | 2011-05-23 17:45:51 +0200 |
|---|---|---|
| committer | Reinhard Tartler <siretart@tauware.de> | 2011-05-24 07:52:31 +0200 |
| commit | 7f3a7b5c40b7fda09cbba4bb53e1ced133970930 (patch) | |
| tree | 7da170e37b9398fa5228d68daa119255f9184226 /doc/encoders.texi | |
| parent | a7a187a1beb8551101b592bf85f0f31a0db22f61 (diff) | |
| download | ffmpeg-7f3a7b5c40b7fda09cbba4bb53e1ced133970930.tar.gz | |
ac3enc: add channel coupling support
Channel coupling is an optional AC-3 feature that increases quality by
combining high frequency information from multiple channels into a
single channel. The per-channel high frequency information is sent with
less accuracy in both the frequency and time domains. This allows more
bits to be used for lower frequencies while preserving enough
information to reconstruct the high frequencies.
Diffstat (limited to 'doc/encoders.texi')
| -rw-r--r-- | doc/encoders.texi | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/doc/encoders.texi b/doc/encoders.texi index 2f3cecde66..760ec4bad9 100644 --- a/doc/encoders.texi +++ b/doc/encoders.texi @@ -365,4 +365,47 @@ is highly recommended that it be left as enabled except for testing purposes. @end table +@subheading Floating-Point-Only AC-3 Encoding Options + +These options are only valid for the floating-point encoder and do not exist +for the fixed-point encoder due to the corresponding features not being +implemented in fixed-point. + +@table @option + +@item -channel_coupling @var{boolean} +Enables/Disables use of channel coupling, which is an optional AC-3 feature +that increases quality by combining high frequency information from multiple +channels into a single channel. The per-channel high frequency information is +sent with less accuracy in both the frequency and time domains. This allows +more bits to be used for lower frequencies while preserving enough information +to reconstruct the high frequencies. This option is enabled by default for the +floating-point encoder and should generally be left as enabled except for +testing purposes or to increase encoding speed. +@table @option +@item -1 +@itemx auto +Selected by Encoder (default) +@item 0 +@itemx off +Disable Channel Coupling +@item 1 +@itemx on +Enable Channel Coupling +@end table + +@item -cpl_start_band @var{number} +Coupling Start Band. Sets the channel coupling start band, from 1 to 15. If a +value higher than the bandwidth is used, it will be reduced to 1 less than the +coupling end band. If @var{auto} is used, the start band will be determined by +the encoder based on the bit rate, sample rate, and channel layout. This option +has no effect if channel coupling is disabled. +@table @option +@item -1 +@itemx auto +Selected by Encoder (default) +@end table + +@end table + @c man end ENCODERS |