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Additional edits from Mark Harris.

--- a/doc/draft-ietf-codec-oggopus.xml

+++ b/doc/draft-ietf-codec-oggopus.xml

@@ -222,8 +222,8 @@

 The granule position of an audio data page encodes the total number of PCM

  samples in the stream up to and including the last fully-decodable sample from

  the last packet completed on that page.

-The granule position of the first audio data page MAY be larger than zero as

- described in <xref target="start_granpos_restrictions"/>.

+The granule position of the first audio data page will usually be larger than

+ zero, as described in <xref target="start_granpos_restrictions"/>.

 </t>

 <t>

@@ -749,8 +749,7 @@

  might include additional fields in the ID header.

 If an ID header has a compatible major version, but a larger minor version,

  an implementation MUST NOT reject it for containing additional data not

- specified here, unless it contains so much additional data that it does not

- complete on the first page.

+ specified here, provided it still completes on the first page.

 </t>

 <section anchor="channel_mapping" title="Channel Mapping">

@@ -794,7 +793,7 @@

 </t>

 <t>Coupled Stream Count 'M' (8 bits, unsigned):

 This is the number of streams whose decoders are to be configured to produce

- two channels.

+ two channels (stereo).

 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

@@ -801,15 +800,16 @@

  can change from packet to packet.

 This is selected by the encoder depending on the bitrate and the audio being

  encoded.

-The original channel count of the audio passed to the encoder is not preserved

- by the lossy compression.

+The original channel count of the audio passed to the encoder is not

+ necessarily preserved by the lossy compression.

 <vspace blankLines="1"/>

 Regardless of the internal channel count, any Opus stream can be decoded as

  mono (a single channel) or stereo (two channels) by appropriate initialization

  of the decoder.

-The 'coupled stream count' field indicates that the first M Opus decoders are

- to be initialized for stereo output, and the remaining (N - M)

- decoders are to be initialized for mono only.

+The 'coupled stream count' field indicates that the decoders for the first M

+ Opus streams are to be initialized for stereo (two-channel) output, and the

+ remaining (N - M) decoders are to be initialized for mono (a single

+ channel) only.

 The total number of decoded channels, (M + N), MUST be no larger than

  255, as there is no way to index more channels than that in the channel

  mapping.