Re: dvd burner can't read cds
2010/2/11 Stephen Powell <zlinuxman@wowway.com>:
> On Thu, 11 Feb 2010 03:13:11 -0500 (EST), Leonardo Canducci wrote:
>> Stephen Powell wrote:
>>> First thing to check: Is the activity light on the drive flashing on
>>> and off at regular intervals? On my system, it's on for about 0.5
>>> seconds, then off for about 0.5 seconds, just like clockwork.
>>> If you don't see that, then either the device never received the
>>> play command or it doesn't support it.
>>
>> I doesn't flash. Drive starts spinning when cd is loaded but doesn't
>> spin when I try to play the disc and returns some error.
>>
>
> You probably know much of this already, but for the sake of others
> listening in ...
>
> There are two basic ways of playing audio CDs: the analog way and
> the digital way. And it's not always obvious which method your
> CD player uses. The original way is the analog way. The program
> sends a "play" command to the CD drive. The CD drive
> reads the digital data from the audio CD, does the digital-to-
> analog conversion inside the drive itself, and sends an analog
> audio signal via the audio cable to the "CD" input of the sound
> card. This audio cable only has three wires: right channel,
> left channel, and ground. (Sometimes an extra ground wire is
> also present, so that each channel has its own ground wire.)
>
> No data is sent across the I/O bus!
> >From the point of view of the host processor, host memory,
> and I/O bus, nothing is happening during the play operation.
> The sound card is simply functioning as an amplifier. Older CD
> players, such as cdplay in the
> cdtool package, use this method. If all you want to do is
> listen to an audio CD, this is by far the most efficient way
> to do it.
The SATA dvd burner in my desktop doesn't have any analog output so
cdplay (or cdcd) does not work (disk is spinning and led is blinking
but no audio).
>
> The newer way is the digital way. The program basically treats
> the audio CD as digital data. Digital data is read from the audio
> CD and transferred across the I/O bus to host
> memory. This digital data is then sent to the regular sound
> port (PCM port) of the sound card, which is a second data
> transfer across the I/O bus. This method obviously uses more
> computer resources than the analog way, but also allows for
> more flexibility. For example, sections of audio data from
> a CD can be captured and put into a .wav file by the program.
> This is called "ripping". This method is used in most
> of the newer media players. I'm pretty sure that Windows
> Media Player in recent releases of Windows uses this method.
In windows (2k and xp at least) you can set the device to handle audio
in digital.
Media player uses digital audio anyway.
>
> The manufacturers of CD drives gain certain economies of
> scale if the same basic CD drive can be used in both digital
> computers and consumer CD players. Consumer CD players require
> the analog method. Therefore, the analog circuitry is present.
> But with DVD players, it may be a different story. It wouldn't
> surprise me if some DVD drives don't have this analog circuitry
> and therefore don't support the traditional "play" command
> for audio CDs. For this type of drive, you may have to use
> a media player that uses the digital, or "ripping" method.
>
> If you're sure that cdplay is addressing the right drive,
> you get an error message, and you don't see the activity
> light on the drive flash on and off at regular intervals,
> it's a pretty good indication that the drive doesn't support
> the "play" command. The fact that it works in Windows doesn't
> mean anything unless you are sure that the media player that
> you're using in Windows is using the analog method.
> Here's one way to be sure. Play a CD in Windows. While
> the CD is playing, unplug the audio cable, either at the
> drive end or the sound card end. If sound suddenly
> disappears, the media player is using the analog method.
> If you continue to hear sound, it's using the digital method.
There's an easier way: change CD volume volume from audio mixer. When
using digital it has no effect (PCM would do).
>
> If you can get the analog method to work under Windows, then
> chances are that cdplay was not talking to the correct drive
> under Linux. Either that or the drive uses some type of
> non-standard command set that the Windows media player
> understands but cdplay, which follows the industry standard
> command set, does not.
It's more complex than that: I tested the unit on a different win xp
pc this morning and everything worked fine (analog included). Same
with ubuntu karmic and slitaz started from a USB stick. On its pc
instead the drive reads cds in digital only with win2k and it doesn't
read them at all in linux (cdplay, cdcd, rhythmbox, ecc.) while
working fine with data cdrom and dvd. It must be some strange wicked
of motherboard, drive and lenny.
--
Leonardo Canducci
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