Loss of data in sound samples
hldswrth
using it to dump a load of tapes. All seemed to be going well until I
tried to convert the samples to data (ZX81 in my case). When I did
this I found that the samples randomly have small sections missing -
as if a small time period has been cut from the sample.
All I can assume is that something is interrupting the recording
process for a short time and the data at that point is lost.
Of course this is useless for recording ZX81 tapes as I can't
necessarily tell if there is missing/incorrect information.
I've uninstalled as much as I can from the computer (I don't use it
for anything else) and removed all unnecessary services/processes, and
also tried switching from the built-in sound hardware to a USB
external mic (iMic), without any improvements.
Anyone else had this problem or any idea how to stop this happening? I
could put the plusdeck in my more recent machine with XP but wanted
the dedicated machine so I can get on with other things at the same
time.
Cheers, Simon
Brian Gaff
checking the transfer mode of the hard drive and if the machine has ever
been used in any way related to multimedia, it could be stuck at pio only.
We had this recently with an hp media machine and the only way to fix it was
to run a visual basic bit of software to change the registry entries, as it
seems that xp, has a bug where if there are six errors the mode cannot be
returned to dma if available any more.
Brian
--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email: bri...@blueyonder.co.uk
______________________________________________________________________________________________________________
"hldswrth" <hlds...@hotmail.com> wrote in message
news:6235b42e-7408-4810...@y24g2000yqb.googlegroups.com...
GzavSnap
Hi Sinon,
Sorry, i can't help you regards hardwares, computers and sound card...
But, somes of problems are due to bad quality, bad records and destroyed
tapes.
| When I did this I found that the samples randomly have small
| sections missing - as if a small time period has been cut from
| the sample.
Have a look to harmonics pictures at http://zx81.ordi5.free.fr/wav
Brian, have a look to :
It's a good sample, but with a cut a the start.
http://zx81.ordi5.free.fr/wav/sample1.wav
It's a crapy sample (the tape move on the magnetic head... bad cassette
mechanism)
http://zx81.ordi5.free.fr/wav/sample2.wav
Yes, it'a common problem on tapes.
The main problem apear if you use two sides on a tape.
The end of the A side program can be located at the start of the B side
program!
If the user press "Stop" ou "Pause", le tape can be crumpled on both sides.
The opposit side is also destroyed... en this program is unable to run.
The tape can alose move up and down on the recording head.
| All I can assume is that something is interrupting the recording
| process for a short time and the data at that point is lost.
In case of loodness ou signals atnenutions, the ZX81 freeze and you had to
reboot it!
| Of course this is useless for recording ZX81 tapes as I can't
| necessarily tell if there is missing/incorrect information.
In case of ZX81, if the cut is located in the D_file (redundent sound at the
end!)
You can retrieve the basic program using EO and a text converter (ZxToken).
Resave the basic program and run it!
But, The Vars segment will be lost...
You can sample two segment, behind the cut and after it with EO.
But, a short piece of program will be lost... in fact, severals bits.
You had to make a bit rotation on the last data bloc to re trive te Byte
integrity.
You can add this new bloc after the first program bloc, but it may hang, il
the D_file, or Vars segment are decayed!
You also can copy a good harmonic on a lood signal, but you if an harmonic
is refreshed, the wrong one must be destroyed.
If a signal is added, a new bit is add to, and it can create a bit decay in
the data bloc!
All datas after this wrong signal will be corrupted!
| Cheers, Simon
Regards,
Xav.
GzavSnap
Brian Gaff
alignment for each individual tape is a must of course as is a machine whose
head is not worn.
Brian
--
Brian Gaff - bri...@blueyonder.co.uk
Note:- In order to reduce spam, any email without 'Brian Gaff'
in the display name may be lost.
Blind user, so no pictures please!
"GzavSnap" <zx81.pas.de.spam.ordi5.chez.free.en.france> wrote in message
news:4b21392c$0$11797$426a...@news.free.fr...
hldswrth
> Well, trying to reclaim bad tapes is a whole other subject. However head
> alignment for each individual tape is a must of course as is a machine whose
> head is not worn.
> Brian
Thanks for the responses. However the issue is not with the tapes at
all, its either with the plusdeck, sound card or operating system.
Each time I dump the same tape, I get gaps in different places. I'm
not talking about the volume dropping to zero, or noise, I mean that
some number of milliseconds of recording has been "cut out" of the
recording. It looks like the recording process is being interrupted,
and during that time stops recording and loses the signal until it
starts again. It's the same as if I'd pressed pause twice in rapid
succession.
This recording worked fine from an external tape deck through the same
sound card on my Windows XP machine, so I can only think that it is
Windows ME or the plusdeck causing this and I've seen enough people
using plusdeck for dumping tapes that it can't be a general issue of
the device.
Looks like I will have to install it into my XP machine, just means I
can't sample tapes and do other things at the same time.
I did look at the hard drive configuration and the DMA checkbox was
unticked, so I have enabled that, and also removed every non-essential
process from the startup so there should be nothing to interrupt the
process.
GzavSnap
>Each time I dump the same tape, I get gaps in different places. I'm
>not talking about the volume dropping to zero, or noise, I mean that
>some number of milliseconds of recording has been "cut out" of the
>recording. It looks like the recording process is being interrupted,
>and during that time stops recording and loses the signal until it
>starts again. It's the same as if I'd pressed pause twice in rapid
>succession.
It seem to have a bad data buffering.
Don't write it in a MP3 format, the sample will be resampled and may be
corrupted.
Write it in a raw Wav format (no compression, no system latency).
Your recording tool seem to buffer datas and hang the system, to compress
this bloc!
Somes of datas are lost during this process.
Daniel Mandic
> I did look at the hard drive configuration and the DMA checkbox was
> unticked, so I have enabled that, and also removed every non-essential
> process from the startup so there should be nothing to interrupt the
> process.
Hi!
You could also try to disable 'full-duplex mode' of the soundcard to
'half-duplex mode', while recording/sampling.
--
Daniel Mandic
hldswrth
computer running Windows XP and I've not had any problems with
recordings since (except for one where I think the screensaver cut in
halfway through the B side). So I guess it was down to the spec of
the old system or Windows ME not being up to doing the recording
uninterrupted.
Cheers, Simon
Lister
Could be Win ME, it's shite!
--
Lister
Posting from his new flat
Daniel Mandic
Is it still possible that the HD and its DMA or UDMA settings are set
too low in the BIOS?
ME shows/leaves DMA checked in the device manager, even when you have
turned down the settings in the BIOS to 'PIO only' mode. (DMA will not
work then under 9x/ME, indeed)
Some Boards (e.g. IBM) do have tricky HD settings in the BIOS, surely
difficult to understand for beginner. AUTO-detect finds the HD size
etc., but DMA mode isn't set properly. PIO only...
--
Daniel Mandic