From 373dc625f82b47096893add42c4472e4a57ab7eb Mon Sep 17 00:00:00 2001 From: Aki Date: Wed, 9 Feb 2022 22:23:03 +0100 Subject: Moved third-party libraries to a separate subdirectory --- contrib/vorbis/doc/libvorbis/overview.html | 136 +++++++++++++++++++++++++++++ 1 file changed, 136 insertions(+) create mode 100644 contrib/vorbis/doc/libvorbis/overview.html (limited to 'contrib/vorbis/doc/libvorbis/overview.html') diff --git a/contrib/vorbis/doc/libvorbis/overview.html b/contrib/vorbis/doc/libvorbis/overview.html new file mode 100644 index 0000000..22cd186 --- /dev/null +++ b/contrib/vorbis/doc/libvorbis/overview.html @@ -0,0 +1,136 @@ + + + +libvorbis - API Overview + + + + + + + + + +

libvorbis documentation

libvorbis version 1.3.2 - 20101101

+ +

Libvorbis API Overview

+ +

Libvorbis is the reference implementation of the Vorbis codec. It is +the lowest-level interface to the Vorbis encoder and decoder, working +with packets directly.

+ +

All libvorbis routines and structures are declared in "vorbis/codec.h".

+ +

Encoding workflow

+ +
    +
  1. Initialize a vorbis_info structure +by calling vorbis_info_init and +then functions from libvorbisenc +on it.
    2. +
  2. Initialize a vorbis_dsp_state +for encoding based on the parameters in the vorbis_info by using vorbis_analysis_init.
    3. +
  3. Initialize a vorbis_comment +structure using vorbis_comment_init, +populate it with any comments you wish to store in the stream, and call +vorbis_analysis_headerout to +get the three Vorbis stream header packets. Output the packets.
    4. +
  4. Initialize a vorbis_block structure +using vorbis_block_init.
    5. +
  5. While there is more audio to encode:
      +
    1. Submit a chunk of audio data using vorbis_analysis_buffer and vorbis_analysis_wrote.
      2. +
    2. Obtain all available blocks using vorbis_analysis_blockout +in a loop. For each block obtained:
        +
      1. Encode the block into a packet (or prepare it for bitrate management) +using vorbis_analysis. (It's a good +idea to always pass the blocks through the bitrate +management mechanism; more information is on the vorbis_analysis page. It does not affect +the resulting packets unless you are actually using a bitrate-managed +mode.)
        2. +
      2. If you are using bitrate management, submit the block using vorbis_bitrate_addblock and obtain +packets using vorbis_bitrate_flushpacket.
        3. +
      3. Output any obtained packets.
        4. +
      3. +
    6. +
  6. Submit an empty buffer to indicate the end of input; this will result +in an end-of-stream packet after all encoding steps are done to it.
    7. +
  7. Destroy the structures using the appropriate vorbis_*_clear routines.
    8. +
+ +

Decoding workflow

+ +Note: if you do not need to do anything more involved than just +decoding the audio from an Ogg Vorbis file, you can use the far simpler +libvorbisfile interface, which +will take care of all of the demuxing and low-level decoding operations +(and even the I/O, if you want) for you. + +
    +
  1. When reading the header packets of an Ogg stream, you can use vorbis_synthesis_idheader to +check whether a stream might be Vorbis.
    2. +
  2. Initialize a vorbis_info and a vorbis_comment structure using the +appropriate vorbis_*_init routines, then pass the first three packets +from the stream (the Vorbis stream header packets) to vorbis_synthesis_headerin in +order. At this point, you can see the comments and basic parameters of +the Vorbis stream.
    3. +
  3. Initialize a vorbis_dsp_state +for decoding based on the parameters in the vorbis_info by using vorbis_synthesis_init.
    4. +
  4. Initialize a vorbis_block structure +using vorbis_block_init.
    5. +
  5. While there are more packets to decode:
      +
    1. Decode the next packet into a block using vorbis_synthesis.
      2. +
    2. Submit the block to the reassembly layer using vorbis_synthesis_blockin.
      3. +
    3. Obtain some decoded audio using vorbis_synthesis_pcmout and vorbis_synthesis_read. Any audio data +returned but not marked as consumed using vorbis_synthesis_read carries +over to the next call to vorbis_synthesis_pcmout.
      4. +
    6. +
  6. Destroy the structures using the appropriate vorbis_*_clear routines.
    7. +
+ +

Metadata workflow

+ +Note: if you do not need to do anything more involved than just +reading the metadata from an Ogg Vorbis file, libvorbisfile can do this for you. + +
    +
  1. Follow the decoding workflow above until you have access to the comments +and basic parameters of the Vorbis stream.
    2. +
  2. If you want to alter the comments, copy the first packet to the output +file, then create a packet for the modified comments using vorbis_commentheader_out and output +it, then copy the third packet and all subsequent packets into the output +file.
    3. +
+ +

+
+ + + + + + + + +

copyright © 2010 Xiph.Org

Ogg Vorbis

libvorbis documentation

libvorbis version 1.3.2 - 20101101

+ + + + + -- cgit v1.1