Difference between revisions of "CD Ripper Settings"

From MythTV Official Wiki
Jump to: navigation, search
(CD ripping content going up)
m (→‎Audio compression)
 
(11 intermediate revisions by 4 users not shown)
Line 1: Line 1:
−
This page is reserved to describe the CD Ripper settings in MythMusic--[[User:Mikec|Mikec]] 22:53, 18 December 2007 (UTC)
+
There are a number of parameters that affect exactly how [[MythMusic]] imports a CD to your MythTV system.  This article provides detailed information about how to select the most appropriate CD Ripper Settings for your needs.
−
Feel free to add if you beat me to it
+
==Ripping CD Music ==
 +
Extracting the digital music information from a CD and putting it onto your Hardrive is referred to as Ripping. MythTV uses an Open source library called [http://xiph.org/paranoia/index.html cdparanoia] to achieve this. There is a common misunderstanding that this is a relatively error free process, as the music is held as a digital stream of numbers, and it should therefore be a simple matter of copying this information stream to the hard drive.
  
−
Some words in CD Paranoia, bit rates, file sizes, formats etc
+
The real problem is that CD Audio is not a random access format like a data file. It was designed to be read from front to back in one continuous sequence. If you drop a bit in the transfer, it system can have moved on many more bits before it re-synchronizes the data stream. This can result in audio clicks. If you then throw in a modern pre-emptive multitasking operating system into the mix, the chances of getting that data off the CD in one piece is not as easy as it seems. Of course if you are then going to compress that music stream to a lossy compressed format such as MP3 or .ogg, then your less likely to care, because you are going to throw much of the music information away. A large click or skip in your music will be easily noticed however, even with lower quality compressed files.  If you are an Audiophile then you will want to treat that CD data stream with velvet gloves, and cdparanoia is a good start. If you are using windows then you might look at [http://users.pandora.be/erik.deppe/cddae.htm DAE].
  
−
==Ripping CD Music ==
+
===Paranoia level===
−
Extracting the digital music information from a CD and putting it onto your Hardrive is referred to as Ripping. MythTV uses an Open source library called CD paranoia to achieve this. There is a misnomer that this is a relatively error free process, as the music is held as a digital stream of numbers, and it should therefore be a simple matter of copying this information stream to the hard drive. The real problem is a normal CD player is a different beast to the CD/DVD drive in your computer system. If you then throw in a modern pre-emptive multitasking operating system into the mix, the chances of getting that data off the CD in one piece is not as easy as it seems. Of course if you are then going to compress that music stream to a nasty format such as MP3 or .ogg then you probably don't really care, because you are going to throw most of the music information away. If you are an Audiophile then you will want to treat that CD data stream with velvet gloves, and CD Paranoia is a good start. If you are using windows then you might look at
+
The paranoia level tells cdparanoia (via MythMusic) how much care it should take in extracting the audio information. The general principle of "less haste, less waste" applies. The faster the extraction the more chance of dropping bits and having holes in your audio stream. This will lead to disappointing results, and the need to re-rip the track.  A high paranoia level is very useful for ripping scratched CDs. Although a badly scratched CD can take literally hours to rip, the resulting files should be (almost) error free.
  
−
===Paranoia level===
+
[[Image:MuiscRip.png]]
−
The paranoia level tells MythTV how much care it should take in extracting the audio information. The general principle of less hast less waste applies. The faster the extraction the more chance of dropping bits and having holes in your audio stream.
 
  
 
== Audio compression ==
 
== Audio compression ==
 
Once CD paranoia has extracted the Music data it will typicall write this out as a  WAV, AIFC, AIFC or raw 16 bit linear PCM data stream.
 
Once CD paranoia has extracted the Music data it will typicall write this out as a  WAV, AIFC, AIFC or raw 16 bit linear PCM data stream.
 
MythTV then compress this raw music stream into a compressed format that reduces the amount of space that music stream takes on your hard drive.
 
MythTV then compress this raw music stream into a compressed format that reduces the amount of space that music stream takes on your hard drive.
 +
 +
[[Image:MusicRip.png]]
 +
 +
 +
 +
The following table details the difference between the different "Encoding" and "Default Rip Quality" options:
 +
{| class="wikitable" border="1"
 +
|-
 +
! Quality
 +
! mp3 Bitrate
 +
! mp3 File Size (per hr)
 +
! ogg Quality (-q=?)
 +
! ogg File Size (per hr)
 +
! FLAC params
 +
! FLAC File Size (per hr)
 +
|-
 +
| Low
 +
| 128 (CBR)
 +
| ?
 +
| 4
 +
| ?
 +
| -m -b 4608 -l 8 -q 0 -r 3,3
 +
| N/A
 +
|-
 +
| Medium
 +
| 192 (VBR)
 +
| ?
 +
| 7
 +
| ?
 +
| same as above
 +
| N/A
 +
|-
 +
| High
 +
| 256 (preset=EXTREME)
 +
| ?
 +
| 10
 +
| ?
 +
| same as above
 +
| N/A
 +
|-
 +
| Perfect
 +
| N/A
 +
| N/A
 +
| N/A
 +
| N/A
 +
| ?
 +
| ?
 +
|-
 +
|}
 +
 +
This info can be found only in the source code, for example [https://github.com/MythTV/mythtv/blob/master/mythplugins/mythmusic/mythmusic/lameencoder.cpp here]
 +
 +
==External Links==
 +
*[http://xiph.org/paranoia/index.html cdparanoia homepage]
 +
*[http://users.pandora.be/erik.deppe/cddae.htm DAE homepage]
 +
*[http://wiki.hydrogenaudio.org/index.php?title=Recommended_Ogg_Vorbis#Recommended_Encoder_Settings Hydrogen Audio Recommended Ogg Vorbis encoding settings], [http://wiki.hydrogenaudio.org/index.php?title=LAME#Recommended_encoder_settings Hydrogen Audio Recommended LAME MP3 encoding settings]

Latest revision as of 14:34, 28 December 2010

There are a number of parameters that affect exactly how MythMusic imports a CD to your MythTV system. This article provides detailed information about how to select the most appropriate CD Ripper Settings for your needs.

Ripping CD Music

Extracting the digital music information from a CD and putting it onto your Hardrive is referred to as Ripping. MythTV uses an Open source library called cdparanoia to achieve this. There is a common misunderstanding that this is a relatively error free process, as the music is held as a digital stream of numbers, and it should therefore be a simple matter of copying this information stream to the hard drive.

The real problem is that CD Audio is not a random access format like a data file. It was designed to be read from front to back in one continuous sequence. If you drop a bit in the transfer, it system can have moved on many more bits before it re-synchronizes the data stream. This can result in audio clicks. If you then throw in a modern pre-emptive multitasking operating system into the mix, the chances of getting that data off the CD in one piece is not as easy as it seems. Of course if you are then going to compress that music stream to a lossy compressed format such as MP3 or .ogg, then your less likely to care, because you are going to throw much of the music information away. A large click or skip in your music will be easily noticed however, even with lower quality compressed files. If you are an Audiophile then you will want to treat that CD data stream with velvet gloves, and cdparanoia is a good start. If you are using windows then you might look at DAE.

Paranoia level

The paranoia level tells cdparanoia (via MythMusic) how much care it should take in extracting the audio information. The general principle of "less haste, less waste" applies. The faster the extraction the more chance of dropping bits and having holes in your audio stream. This will lead to disappointing results, and the need to re-rip the track. A high paranoia level is very useful for ripping scratched CDs. Although a badly scratched CD can take literally hours to rip, the resulting files should be (almost) error free.

MuiscRip.png

Audio compression

Once CD paranoia has extracted the Music data it will typicall write this out as a WAV, AIFC, AIFC or raw 16 bit linear PCM data stream. MythTV then compress this raw music stream into a compressed format that reduces the amount of space that music stream takes on your hard drive.

MusicRip.png


The following table details the difference between the different "Encoding" and "Default Rip Quality" options:

Quality mp3 Bitrate mp3 File Size (per hr) ogg Quality (-q=?) ogg File Size (per hr) FLAC params FLAC File Size (per hr)
Low 128 (CBR)  ? 4  ? -m -b 4608 -l 8 -q 0 -r 3,3 N/A
Medium 192 (VBR)  ? 7  ? same as above N/A
High 256 (preset=EXTREME)  ? 10  ? same as above N/A
Perfect N/A N/A N/A N/A  ?  ?

This info can be found only in the source code, for example here

External Links

Retrieved from "http://www.mythtv.org/wiki?title=CD_Ripper_Settings&oldid=50594"