diff options
| author | Ralph Giles <giles@mozilla.com> | 2013-01-12 05:11:07 +0400 |
|---|---|---|
| committer | Ralph Giles <giles@mozilla.com> | 2013-01-12 05:11:07 +0400 |
| commit | e7aa6cb9a09cbd3538b0d41fc86eb28c2fc3c0bd (patch) | |
| tree | 48a15b724ef340d183345638ca5f2af8cdc476df | |
| parent | fc113b735bbece4d3dfada9f3335c9008e08345c (diff) | |
Minor clarifications to the channel mapping section.
Mostly just being more verbose.
| -rw-r--r-- | doc/draft-ietf-codec-oggopus.xml | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/doc/draft-ietf-codec-oggopus.xml b/doc/draft-ietf-codec-oggopus.xml index 5162dd8d..7d55af90 100644 --- a/doc/draft-ietf-codec-oggopus.xml +++ b/doc/draft-ietf-codec-oggopus.xml @@ -666,7 +666,7 @@ This MUST be no larger than the total number of streams, N. <vspace blankLines="1"/> Each packet in an Opus stream has an internal channel count of 1 or 2, which can change from packet to packet. -This is selected by the encoder depending on the bitrate and the contents being +This is selected by the encoder depending on the bitrate and the audio being encoded. The original channel count of the encoder input is not preserved by the lossy compression. @@ -723,8 +723,9 @@ Allowed numbers of channels: 1 or 2. </list> <spanx style="strong">Special mapping</spanx>: This channel mapping value also indicates that the contents consists of a single Opus stream that is stereo if - and only if C==2, with stream index 0 mapped to channel 0, and (if stereo) - stream index 1 mapped to channel 1. + and only if C==2, with stream index 0 mapped to output channel 0 (mono, or + left channel) and stream index 1 mapped to output channel 1 (right channel) + if stereo. When the 'channel mapping family' octet has this value, the channel mapping table MUST be omitted from the ID header packet. <vspace blankLines="1"/> @@ -754,9 +755,11 @@ The ordering is different from the one used by the FLAC <xref target="flac"/> formats, although the configurations match, so correct ordering requires permutation of the output channels when encoding from or decoding to those formats. +'LFE' here refers to a Low Frequency Effects, often mapped to a subwoofer + with no particular spacial position. Implementations SHOULD identify 'side' or 'rear' speaker locations with - 'surround' as appropriate when interfacing with audio formats or systems - which prefer that terminology. + 'surround' and 'back' as appropriate when interfacing with audio formats + or systems which prefer that terminology. <vspace blankLines="1"/> </t> <t>Family 255 (no defined channel meaning): |