From 8c8a5e12c09147d5fdd8976eaba7154391e2fe07 Mon Sep 17 00:00:00 2001 From: Andre Noll Date: Sat, 6 Aug 2011 17:10:20 +0200 Subject: [PATCH] doc: Add flac documentation to manual and FEATURES. --- FEATURES | 2 +- web/manual.m4 | 23 ++++++++++++++++++----- 2 files changed, 19 insertions(+), 6 deletions(-) diff --git a/FEATURES b/FEATURES index 2839d79c..613acc19 100644 --- a/FEATURES +++ b/FEATURES @@ -5,7 +5,7 @@ Features * Runs on Linux, Mac OS, FreeBSD, NetBSD, Solaris and probably other Unixes - * Mp3, ogg/vorbis, ogg/speex, aac (m4a) and wma support + * Mp3, ogg/vorbis, ogg/speex, aac (m4a), wma and flac support * Native Alsa, OSS, CoreAudio output support * Support for ESD, Pulseaudio, AIX, Solaris, IRIX through libao * Local or remote http, dccp and udp network audio streaming diff --git a/web/manual.m4 b/web/manual.m4 index 6bddbf11..7eecdbb3 100644 --- a/web/manual.m4 +++ b/web/manual.m4 @@ -254,6 +254,10 @@ Optional: - XREFERENCE(http://www.speex.org/, speex). In order to stream or decode speex files, libspeex (libspeex-dev) is required. + - XREFERENCE(http://flac.sourceforge.net/, flac). To stream + or decode files encoded with the _Free Lossless Audio Codec_, + libFLAC (libFLAC-dev) must be installed. + - XREFERENCE(ftp://ftp.alsa-project.org/pub/lib/, alsa-lib). On Linux, you'll need to have ALSA's development package libasound2-dev installed. @@ -1111,6 +1115,15 @@ how meta data about the file is to be encoded. The bit stream of WMA is composed of superframes, each containing one or more frames of 2048 samples. For 16 bit stereo a WMA superframe is about 8K large. +*FLAC* + +The Free Lossless Audio Codec (FLAC) compresses audio without quality +loss. It gives better compression ratios than a general purpose +compressor like zip or bzip2 because FLAC is designed specifically +for audio. A FLAC-encoded file consits of frames of varying size, up +to 16K. Each frame starts with a header that contains all information +necessary to decode the frame. + Meta data ~~~~~~~~~ @@ -1123,10 +1136,10 @@ title, album, year and comment tags. Each of these can only be at most 32 characters long. ID3, version 2 is much more flexible but requires a separate library being installed for paraslash to support it. -Ogg vorbis files contain meta data as Vorbis comments, which are -typically implemented as strings of the form "[TAG]=[VALUE]". Unlike -ID3 version 1 tags, one may use whichever tags are appropriate for -the content. +Ogg vorbis, ogg speex and flac files contain meta data as Vorbis +comments, which are typically implemented as strings of the form +"[TAG]=[VALUE]". Unlike ID3 version 1 tags, one may use whichever +tags are appropriate for the content. AAC files usually use the MPEG-4 container format for storing meta data while WMA files wrap meta data as special objects within the @@ -1144,7 +1157,7 @@ paraslash uses the word "chunk" as common term for the building blocks of an audio file. For MP3 files, a chunk is the same as an MP3 frame, while for OGG files a chunk is an OGG page, etc. Therefore the chunk size varies considerably between audio formats, from a few hundred -bytes (MP3) up to 8K (WMA). +bytes (MP3) up to 16K (FLAC). The chunk table contains the offsets within the audio file that correspond to the chunk boundaries of the file. Like the meta data, -- 2.30.2