Can I use a DVD recorder for audio only? - AVS Forum
Forum Jump: 
 
Thread Tools
post #1 of 14 Old 08-31-2003, 07:28 AM - Thread Starter
Senior Member
 
Steve O's Avatar
 
Join Date: Jan 2001
Posts: 330
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Another noobie DVD recorder question...

Can DVD recorders be used for audio only? I have some records that I'd like to get backed up. I'd also be interested in recording CDs so I could create a LONG compilation to play at parties and whatnot.

(and yes, I understand that audio on DVD recorder is going to be analog only)

Does anyone have any experience in audio-only recording with a DVD recorder?

Thanks!
-Steve
Steve O is offline  
Sponsored Links
Advertisement
 
post #2 of 14 Old 09-01-2003, 02:30 PM
AVS Special Member
 
dugpa's Avatar
 
Join Date: May 2003
Location: Carrollton, TX
Posts: 1,093
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
You kind of lost me there a few places in your post, but I think I have it figured out. If you mean can you record cds with your recorder, no, I have yet to hear of one that will record cd-r's. If you mean could you record a dvd-r (or what ever dvd recordable format the recorder uses) with just audio and take advantage of longer lengths available at slower speeds, I can't imagine why you couldn't do this. Just don't hook up anything to the video in or better yet hook up a black source. Though I've never actually tried this, I can't imagine why it wouldn't work. Your audio will be dolby digital, so you're stepping down from cd quality, and I have no idea how the various recorders handle audio bit rates at slower speeds, though I assume it would lower them. I had an e50 for a couple of weeks before returning it and I never recorded anything lower than SP speed, so I didn't compare the audio at lower rates.

DVD collection
LD collection

Congratulations. You have just discovered the secret message. Please send your answer to Old Pink, care of the Funny Farm, Chalfont.
dugpa is offline  
post #3 of 14 Old 09-01-2003, 06:06 PM - Thread Starter
Senior Member
 
Steve O's Avatar
 
Join Date: Jan 2001
Posts: 330
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I am, of course, wanting a DVD recorder for all of the usual reasons. I was just wondering really what would happen if I recorded audio only. I understand that I won't be on a CD-R but instead a DVD-R.

I guess the reason I asked goes back to the old VHS hi-fi days. At least on the deck that I had at the time, if a video signal wasn't present, the thing got all confused on the audio.

The question about length, I suppose, is better asked like this... do DVD recorders record in VBR (variable bitrate) or CBR (constant bitrate)? If constant, then the thing is going to allocate just as many bits to a black screen as it would to a very active video. Whereas with VBR, the compressed video would take up virtually no space at all if all it was compresing was nothing.

If someone can maybe try this, it would be great... unplug the video from your DVD recorder and record. What does it do? Does it record the audio?

(EDIT: I pulled down the Panasonic E80 manual since that's the one I'm really looking at. It doesn't say anything about audio-only recording as far as I can tell, but it DOES allow for PCM recording of the audio as mentioned in the following: "Audio is recorded using Dolby Digital stereo, enabling high quality sound recordings. When recording in XP mode it is possible to use LPCM (2 channel) to achieve sound recordings of even higher quality." It also talks about the video encoding and it allows for VBR. There's a setting in the menu under Video for "Hybrid VBR Resolution" which has the following options: Automatic:Video compression is automated providing efficient recording. Fixed: Video compression is fixed when recording providing smooth video play. It also says the following as far as time left on the disc: "This units records using a VBR (Variable bit recording) data compression system to vary recorded data segments to match video data segments which may cause differences in the displayed amount of time and space remaining for recording." So if it can handle recording of a "blank" video signal, then it can probably fit a decent amount of audio on a single 4.7GB DVD-R.)

-Steve
Steve O is offline  
post #4 of 14 Old 09-02-2003, 03:59 AM
Advanced Member
 
btokars's Avatar
 
Join Date: Jul 2002
Location: San Francisco
Posts: 790
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
I just came back from a 4-day train trip across Canada and before I left I recorded audio from DISH Network's music feeds to have some fresh music for our trip. While technically it wasn't audio only because there is a video signel associated with it, the result was quite good. Got 4 hours of music on each DVD (at LP speed) and it sounded fine (not great but quite OK).
btokars is offline  
post #5 of 14 Old 09-02-2003, 08:32 AM
AVS Special Member
 
dugpa's Avatar
 
Join Date: May 2003
Location: Carrollton, TX
Posts: 1,093
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
(EDIT: I pulled down the Panasonic E80 manual since that's the one I'm really looking at. It doesn't say anything about audio-only recording as far as I can tell, but it DOES allow for PCM recording of the audio as mentioned in the following: "Audio is recorded using Dolby Digital stereo, enabling high quality sound recordings. When recording in XP mode it is possible to use LPCM (2 channel) to achieve sound recordings of even higher quality."
-Steve [/b]
But since PCM is only available in XP mode, that means you'd only have an hour or so of record time. Might as well just burn a cdr then. Even with a black signal I can't imagine you'd gain that much more time over an hour. Though I guess someone would have to actually try this to find out for sure.

DVD collection
LD collection

Congratulations. You have just discovered the secret message. Please send your answer to Old Pink, care of the Funny Farm, Chalfont.
dugpa is offline  
post #6 of 14 Old 09-03-2003, 05:10 PM - Thread Starter
Senior Member
 
Steve O's Avatar
 
Join Date: Jan 2001
Posts: 330
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
But since PCM is only available in XP mode, that means you'd only have an hour or so of record time.
An hour or so with acutal video, but how far can VBR mpeg compression compress a blank screen? Pretty far, I'd think.

-Steve
Steve O is offline  
post #7 of 14 Old 09-03-2003, 05:59 PM
AVS Special Member
 
vferrari's Avatar
 
Join Date: May 2002
Location: Wash DC Metro Area
Posts: 3,693
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
An hour or so with acutal video, but how far can VBR mpeg compression compress a blank screen? Pretty far, I'd think.
Steve,

That's not how it works. The Panny does record using VBR for video compression. However, if you tell it to record in XP mode, even a pure black signal will still be recorded at an avg. bitrate that will provide an hour's worth of 704x480 video (max) with PCM audio on a single disk. You just won't get much fluxuation on the avg bitrate and you'll have one helluva good looking black signal (now that they've fixed the black level bug - antoher story) and 1-hours worth of PCM audio (no more). XP mode, as well as all the other modes SP (2-hr), LP (4-hr), and EP (6-hr) record a Dolby Digital 2.0 (AC3) compressed audio elementary stream at a fixed 256 kbps bitrate and 48kHz sample rate. Therefore, if all you want is a long duration DVD of audio programming, and can live with AC3 compressed audio, I'd pick EP mode since you won't take an audio quality hit vs. the other record modes.

Vic

The Future ain't what it used to be...
vferrari is offline  
post #8 of 14 Old 09-03-2003, 08:03 PM
dgb
Senior Member
 
dgb's Avatar
 
Join Date: Jun 2002
Location: Madison, AL
Posts: 296
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
When recording to disk the time limits for the various modes of the Panasonic recorders are fixed, but when recording to hard drive and then dubbing in high speed mode the recording length is more dependant on the actual file size (there is still a six hour limit on the length of an individual recording.)

A 20 minute XP recording using PCM audio to the hard drive of my E80 is reported as 396 MB in the dubbing menu. Based on that, a DVD should hold about 3 hours and 40 minutes of PCM audio with no video signal.

David

edit:
The same 20 minutes of audio at EP is 122 MB, so it may be possible to dub about 12 hours of AC3 audio onto one disk. Dubbing 2 hours of the XP recording (six copies of it) to DVD-RAM worked, but I have not tried dubbing to DVD-R.
dgb is offline  
post #9 of 14 Old 09-03-2003, 08:40 PM
AVS Special Member
 
vferrari's Avatar
 
Join Date: May 2002
Location: Wash DC Metro Area
Posts: 3,693
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
A 20 minute XP recording using PCM audio to the hard drive of my E80 is reported as 396 MB in the dubbing menu. Based on that, a DVD should hold about 3 hours and 40 minutes of PCM audio with no video signal.
Interesting. If that is the case, shouldn't you just be able to hit the record button and record more than 1 hour of "no video" PCM audio direct to DVD disk or will it stop at one hour when it "thinks" the 4 GB disk should be full based on a typical XP average vbr? If there is no video input signal present, what is recorded in the video stream (mpeg2 bit rate actually drops to near zero)?

Edit: Based on your edited post, dgb, apparently you have confirmed that this works direct to DVD-RAM as well as to the HDD.

I take it back Steve O. It appears that IS how it works...

Vic

The Future ain't what it used to be...
vferrari is offline  
post #10 of 14 Old 09-03-2003, 09:01 PM
dgb
Senior Member
 
dgb's Avatar
 
Join Date: Jun 2002
Location: Madison, AL
Posts: 296
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
The edit referred to a *dub* to RAM not a direct recording. The DVD-RAM disk I dubbed to shows 0:00 free when I select it as the active drive, but 1964 MB free in dubbing mode. So the recorder sees it as full for recording directly, but nearly half empty for dubbing!

Looking at the bitrates in the status display, PCM is 1 Mbps, the EP recording is 0.2 Mbps. An I-frame is only about 75kb in SP and just 15 kb in EP, so not zero but pretty low.

Dav
dgb is offline  
post #11 of 14 Old 09-03-2003, 10:46 PM
AVS Special Member
 
vferrari's Avatar
 
Join Date: May 2002
Location: Wash DC Metro Area
Posts: 3,693
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
That is strange...

Vic

The Future ain't what it used to be...
vferrari is offline  
post #12 of 14 Old 09-04-2003, 06:21 PM
dgb
Senior Member
 
dgb's Avatar
 
Join Date: Jun 2002
Location: Madison, AL
Posts: 296
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I dubbed 6 copies of the 20 minute EP recording I made yesterday to DVD-R in high speed mode, then another 6 copies, then an additional 12 for a total of 8 hours. When the third dub completed there was space for another 4 hours worth of the audio only recordings. However, when I hit the dub button it popped up a message about being a non-recordable disk even though it showed 1465 MB free space.

I suspect I could have put the full 12 hours on the disk if I had dubbed 36 copies all at once, though I'd have to try it to be certain. The disk with 24 copies (8 hours) did finalize and play on the E80 and a Sony player.

David
dgb is offline  
post #13 of 14 Old 09-04-2003, 07:33 PM
Senior Member
 
AmoebaMan's Avatar
 
Join Date: Jun 2002
Location: Seattle
Posts: 230
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I read somewhere that the audio stream stays the same quality regardless of the video speed, so I started recording 6-hour blocks of my cable music channel for a buddy in an isolated place.

Seemed to work like a charm. The video is naturally crappy, but it's clear enough to read the song names. And the music sounds perfect.

-AmoebaMan
AmoebaMan is offline  
post #14 of 14 Old 09-09-2003, 05:08 AM
Advanced Member
 
Joel Graffman's Avatar
 
Join Date: Sep 2002
Location: Palm City, FL
Posts: 821
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I have been making audio recordings to DVD-R for about a year, works great. Here's what I do.

For a number of years I have been using a VCR as an audio recorder, as it can record a complete opera on one tape. I have never looked at the specs, but recording from FM radio, even using long play mode, I can't tell the difference from the original broadcast. Over the years this resulted in a tape library that took up a lot of shelf space.

When I bought my Panasonic DMR-E20, I recorded the VCR tapes to DVD-Rs using the 4 hour mode. Again, I haven't seen the specs, but to my ear I cannot tell the difference. Saved a lot of shelf space.
Joel Graffman is offline  
Closed Thread DVD Recorders (Standard Def)

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off