diff --git a/doc/draft-ietf-codec-oggopus.xml b/doc/draft-ietf-codec-oggopus.xml index e3eadc9353c77c4e97f179c3872ec0a171b7233c..ff1ebf586dd258e1a8158f2dc313959a8129137f 100644 --- a/doc/draft-ietf-codec-oggopus.xml +++ b/doc/draft-ietf-codec-oggopus.xml @@ -580,7 +580,7 @@ An Opus stream contains exactly two mandatory header packets: The fields in the identification (ID) header have the following meaning: -Magic Signature: +Magic Signature: This is an 8-octet (64-bit) field that allows codec identification and is human-readable. @@ -599,7 +599,7 @@ Starting with "Op" helps distinguish it from audio data packets, as this is an invalid TOC sequence. -Version (8 bits, unsigned): +Version (8 bits, unsigned): The version number MUST always be '1' for this version of the encapsulation specification. @@ -616,7 +616,7 @@ The initial version '1' was chosen to keep implementations from relying on this octet as a null terminator for the "OpusHead" string. -Output Channel Count 'C' (8 bits, unsigned): +Output Channel Count 'C' (8 bits, unsigned): This is the number of output channels. This might be different than the number of encoded channels, which can change @@ -627,7 +627,7 @@ The maximum allowable value depends on the channel mapping family, and might be See for details. -Pre-skip (16 bits, unsigned, little +Pre-skip (16 bits, unsigned, little endian): This is the number of samples (at 48 kHz) to discard from the decoder @@ -638,7 +638,7 @@ When cropping the beginning of existing Ogg Opus streams, a pre-skip of at convergence in the decoder. -Input Sample Rate (32 bits, unsigned, little +Input Sample Rate (32 bits, unsigned, little endian): This field is not the sample rate to use for @@ -683,8 +683,7 @@ Rates outside this range MAY be ignored by falling back to the default rate of 48 kHz instead. -Output Gain (16 bits, signed, little - endian): +Output Gain (16 bits, signed, little endian): This is a gain to be applied by the decoder. It is 20*log10 of the factor to scale the decoder output by to achieve the @@ -722,8 +721,7 @@ The large range serves in part to ensure that gain can always be losslessly saturating. -Channel Mapping Family (8 bits, - unsigned): +Channel Mapping Family (8 bits, unsigned): This octet indicates the order and semantic meaning of the output channels. @@ -732,7 +730,7 @@ Each possible value of this octet indicates a mapping family, which defines a allowed channel count. The details are described in . -Channel Mapping Table: +Channel Mapping Table: This table defines the mapping from encoded streams to output channels. It is omitted when the channel mapping family is 0, but REQUIRED otherwise. Its contents are specified in . @@ -782,7 +780,7 @@ The order and meaning of these channels are defined by a channel mapping, The fields in the channel mapping table have the following meaning: -Stream Count 'N' (8 bits, unsigned): +Stream Count 'N' (8 bits, unsigned): This is the total number of streams encoded in each Ogg packet. This value is necessary to correctly parse the packed Opus packets inside an @@ -793,7 +791,7 @@ This value MUST NOT be zero, as without at least one Opus packet with a valid For channel mapping family 0, this value defaults to 1, and is not coded. -Coupled Stream Count 'M' (8 bits, unsigned): +Coupled Stream Count 'M' (8 bits, unsigned): This is the number of streams whose decoders are to be configured to produce two channels. This MUST be no larger than the total number of streams, N. @@ -818,7 +816,7 @@ For channel mapping family 0, this value defaults to C-1 (i.e., 0 for mono and 1 for stereo), and is not coded. -Channel Mapping (8*C bits): +Channel Mapping (8*C bits): This contains one octet per output channel, indicating which decoded channel is to be used for each one. Let 'index' be the value of this octet for a particular output channel. @@ -859,7 +857,7 @@ RTP mapping. 1 channel: monophonic (mono). 2 channels: stereo (left, right). -Special mapping: This channel mapping value also +Special mapping: 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 output channel 0 (mono, or left channel) and stream index 1 mapped to output channel 1 (right channel) @@ -1103,7 +1101,7 @@ The comment header consists of a 64-bit magic signature, followed by data in Vorbis, except (like Ogg Theora and Speex) the final "framing bit" specified in the Vorbis spec is not present. -Magic Signature: +Magic Signature: This is an 8-octet (64-bit) field that allows codec identification and is human-readable. @@ -1122,15 +1120,14 @@ Starting with "Op" helps distinguish it from audio data packets, as this is an invalid TOC sequence. -Vendor String Length (32 bits, unsigned, - little endian): +Vendor String Length (32 bits, unsigned, little endian): This field gives the length of the following vendor string, in octets. It MUST NOT indicate that the vendor string is longer than the rest of the packet. -Vendor String (variable length, UTF-8 vector): +Vendor String (variable length, UTF-8 vector): This is a simple human-readable tag for vendor information, encoded as a UTF-8 string . @@ -1142,8 +1139,7 @@ User-facing encoding applications can use the 'ENCODER' user comment tag to identify themselves. -User Comment List Length (32 bits, unsigned, - little endian): +User Comment List Length (32 bits, unsigned, little endian): This field indicates the number of user-supplied comments. It MAY indicate there are zero user-supplied comments, in which case there are @@ -1152,8 +1148,7 @@ It MUST NOT indicate that there are so many comments that the comment string lengths would require more data than is available in the rest of the packet. -User Comment #i String Length (32 bits, - unsigned, little endian): +User Comment #i String Length (32 bits, unsigned, little endian): This field gives the length of the following user comment string, in octets. There is one for each user comment indicated by the 'user comment list length' @@ -1161,8 +1156,7 @@ There is one for each user comment indicated by the 'user comment list length' It MUST NOT indicate that the string is longer than the rest of the packet. -User Comment #i String (variable length, UTF-8 - vector): +User Comment #i String (variable length, UTF-8 vector): This field contains a single user comment string. There is one for each user comment indicated by the 'user comment list length'