how to improve the audio capture? my method.

[sunmanking]

i'm much interested in line-in volume settings as
i'd like to improve the audio as much as possible.

my line-in volume control is about 80 %, which i think
it's good enough.

yet, when i listen to the audio track, there are some times
when the voices become a little bit "metallic", not even
for one second, but you can notice that. i center the wave,
apply noise reduction (with a very good sample profile)
and then normalize to 100%. but it's still there. the problem
it seems to me lies in the audio as captured, since it already
has that "metallic" tone (very few times).

this forum is about capturing, but that process involves both
video and audio. so i guess most of us are interested in
learning how to get the best audio and/or correctlt apply
effects to it.

If anyone knows, please share your knowledge

Thanks in advance,

Sunmanking

[HOOKEDONTECH]

I used to have that same problem when capturing (dv) video from a digital camcorder and then compressing the avi's to vcd or svcd with TmpegEnc. The finished mpg's would have that annoying metalic sound. I have since found that if i captiure and then compress to vcd or svcd using ulead 5.0 the metalic sound in the audio is eliminated.

[liquid217]

the metallic sound you are referring to is the result of converting audio from 48Khz to 44.1Khz. (down sampling). If your capturing from an analog source, you should capture at 44.1Khz... which is vcd/svcd standard. You can use tmpgenc to downsample correctly, but you need to change a few things.. The first thing you could do is goto.. options...and goto the audio tab... if you havre a newer version of tmpgenc, you can select the "high quality" downsampling option. Otherwise, just get ssrc, and use that as the sampling convertor. (much higher quality that tmpgenc's own convertor... and without the metallic sound). you can get ssrc here.
http://www.afterdawn.com/software/audio_software/audio_tools/ssrc.cfm

[sunmanking]

Hello,

Thanks for keeping this thread on!

In my case, and I guess it's many people's case too, has to
do with capturing the audio+video from a VHS videotape
(VCR). The audio in the videotape has some background
noise, as usual, but it can be removed with background
noise filters in any decent audio editor.

I have played the videotape again. I use a composite cable
to capture video and an audio(left-right)--audio cable
to capture the audio. The audio cable is plugged to the
TV card and then there's a second cable that links the
TV card with the sound card. Audio capturing is at
44.100 Hz, 16-bit, stereo.

When I have played the videotape the sound was ok.
Some noise but NO "metalic" voices at all.

Once I get the capture done, I play the video and ...
there it is! The metalic sound every once in a while.
Not frequently at all, but just a every once and then.
And I don't think it's distortion, since I can see in the
audio editor the wave is not reaching the top when
that happens.

All this makes me think that the problem is somewhere
between the VCR and the TV card or sound card.

Has anyone else been through this mess and finally
seen "the light"?

Thanks...............

sunmanking

[liquid217]

well im not entirely sure, but ill take a guess here.. under control pannel, goto multimedia..under the audio tab, select the advanced properties for recording.. set the conversion quality to best. You might try experimenting with dropping the hardware acceleration also. Another possibility is that you need to udate your sound card drivers.

[Martok]

The "Metalic" noises you're hearing are most likely the artifacts of MPEG compression (not downsampling).
TMPGEnc does NOT handle audio compression well.
No compression is perfect, but try BeSweet...Much better for audio than TMPGEnc.

[dphirschler]

I would have to agree with Martok's post. TMPGenc does not encode audio very well. Use an external audio encoder (tooLAME) for better results.

I used to have problems with audio from the VCR overloading my soundcard's preamp. My solution was to run the sound through my DAT deck (which handles the strong audio signals better), then send the audio out through S/PDIF to my soundcard.

If you don't have a DAT deck or a digital sound card, then try running it through your receiver before going to the soundcard's line-in. It might work going through a tape deck too. You might have to have a cassette in the recording deck and hit pause & record to make the sound pass through.


Darryl

[sunmanking]

hello guys

you won't believe this but i am appalled... after MANY MANY
tries and different settings, i've told myself... man, maybe
all the trouble is in the sound card itself... it's an avance
logic ASL4000. it came with the computer so there's nothing
i could do. it handles full duplex and that's basically what
i needed to rip vhs tapes. the thing is that i'm made up
my mind and switched the asl4000 for my good old
sound blaster 16-bit... that an antique nowadays! :P

so i've plugged it in, made the same recording (this time
only the audio) from the vhs and... gues what??!!

no clipping nor metallic sounds!!! so the problem, seemingly,
was the CRAPPY soundcard!!

next, i've been to the computer store and bought a
sound blaster 4.1 (budget is budget...) which supports
full-duplex and should be somewhat better from what i've
read in the specs. the sb16 has no full-duplex.

so now it's time to plug it in! i'll write back after testing
and playing around with it.

greetings,

sunmanking

[Divx-Trdr]

WOW, awesome audio advice goin on here, may I ask a Q
Im using an ATI TV wonder card, capture software is iuVCR(cuz I can capture higher than 320x240 res using this software) my VHS tapes are being played thru a VCR, the video is composite signal, and audio has been input thru both Line-in, and capture card inputs but anyway I slice it, my audio will NOT sync. I get this with ANY vhs tape I capture.
My video compression is HUFFY 1.3.1 and audio is PCM 41,000khz 128kbps stereo. i know its not my HDD as I get NO dropped frames. and i am able to capture from the cableTV signal with NO problem at ANY resolution. Its only when I capture from old VHS tapes that the audio is at least 2 secs behind the video from the beginning, and as the movie plays on, the audio gets further & further out of sync!!

any suggestions?? I have tried just about EVERY possible capturing software there is, so please, if you have a suggestion, let me know specific settings!!

Thanks!

[sunmanking]

hi,

first, i'll tell you that the sb 4.1 did finally solve all my
trouble! now there are no metallic sounds or voices
anywhere, no clipping no nothing, no trouble!

concerning your question, iuvcr is an outstanding
nice piece of capturing software indeed.

i'd suggest you read the help file since at the FAQ
the auther explains what checkboxes you must tick
in order to avoid any sync problems. also, i don't know
what cpu you have BUT bear in mind that you're grabbing
at a way TOO HIGH resolution. i've read some very
well and technical vhs capturing guides (since that
is my main interest and what i'm actually doing) and
they advice as well as I advice you from my own experience...

capture VHS at 352*288 (pal) or the corresponding
NTSC. there is no need to capture at higher res. just
waste of time, hd, conversion time etc...

lower the cap res and let us know if you succeed.

greetings,

sunmanking

[Divx-Trdr]

WOW,
what a difference changing the RES made!
I used VirtualDUB 1.4.13 and capped at 340x280(NTSC) and the audio was right on for the ENTIRE capture!!

Im currently converting this newly made AVI file into an SVCD format to see how it will look on my stand alone DVD player.

Thanks for the TIP, if this comes out looking great on the TV, I will be able to capture ALL the remaining VHS & 8MM tapes I have to SVCD!

[sunmanking]

hi,

glad that you're enjoying. i can already assure you the
video will look GREAT. you'll see

try to convert to xvcd and svcd and see if there are
any differences. there shouldn't be. you'll see by
yourself.

greetings,

sunmanking

[Bizuser]

Great information!

I've captured video/audio at 352x240 and not had synch problems, then captured at 480x480 and had synch problems. My synch problems are that the synch starts out perfect, but gradually drifts by about 2 seconds after about 30 minutes - but only after authoring to SVCD (the native captured mpeg2 file plays just fine!). Note: I'm just using the built-in capture feature of ATI's package, and capturing direct to MPEG2 (for SVCD; MPEG1 for VCD). I'm assuming posters in this message are capturing to AVI first? I'm trying to avoid that if possible, but will do it if it's strongly recommended! I'm also going to download and try iuVCR, based on posts here - $25 is peanuts if it does the job it says it does! So to recap - I capture using ATI's built in software; capture at 352x240 using MPEG1 then author to VCD - no problem; capture at 480x480 using MPEG2 then author to SVCD - audio drift after 30 minutes.

While I understand that you don't need to capture at anything higher than 352x240 for VHS capture, I'm having this problem capturing regular cable feed, which obviously will benefit somewhat from being captured at a higher res.

Also, if I want to burn SVCD rather than VCD, then I would assume that I 'should' capture at 480x480 (even for VHS capture) since that's the native resolution for SVCD; otherwise, I'm going to have to resize. My computer can handle it (like I said - the MPEG2 native capture file plays great on the PC - only goes bad after authoring to SVCD). My assumption is that there's a problem in how ATI is writing the MPEG2 stream, such that when you author as SVCD, it gets messed up.

I've tried demuxing/remuxing with TMPG, remuxing with bbMPEG, but nothing cures the slow audio drift. Video looks great, though!!!

Divx-Trdr fixed his problem by reducing res, but if you 'do' need to capture at higher res, what's the fundamental cause of the problem?

Thanks for the help and info everyone!

[dphirschler]

Tell me, Bizuser, were you dropping frames at the higher resolutions? That sounds like it was the problem. Your computer can keep up with the lower res capture and so does not drop frames and subsequently get out of sync with the audio. That's my hunch anyway.


Darryl

[Bizuser]

Nope, not at all - no drops (at least, no indication of drops). The original mpeg2 file capture plays great in ATI's 'file player' - full audio synch all the way to the end. But read on ...

However - could this be the issue - I'm dropping frames without realizing it; the mpeg2 file produced is still playable (no drift) in ati file player, but when you 'process' that file - demux/mux - or even just SVCD author it - these dropped frames DO become significant. Certainly a gradual drift 'must' be caused by something like this! To verify, I should capture the exact same source, same mpeg2 settings, but drop resolution ONLY to 352x240. If that works fine, then your theory must be correct.

When I first posted in this thread, I was asking myself 'why did I demux/remux in the first place?'. It was because, when I first tried to simply author the SVCD image using VCDEasy, I got a massive number of errors in the log. Very oddball messages, suggesting the 'subtitles were CVCD format' or similar (my source was simple capture from a tv show, no subtitles, no nothin')! I searched high and low and found no explanation for this, but did stumble across a tip about demux/remux, so did that in TMPG, and now I got a great (error free) VCDEasy author of SVCD file. But now, the actual SVCD plays with the audio drift.

So all along I've been assuming the problem was with the MPEG2 stream - but maybe it's just a simple frame drop issue.

I'll retest and post results. Anyone else seen those 'subtitle/CVCD' messages? (CVCD is "Chinese VCD" I believe, a variation of VCD?).

[Acidagent]

[quote="Divx-Trdr"]WOW, awesome audio advice goin on here, may I ask a Q
Im using an ATI TV wonder card, capture software is iuVCR(cuz I can capture higher than 320x240 res using this software) my VHS tapes are being played thru a VCR, the video is composite signal, and audio has been input thru both Line-in, and capture card inputs but anyway I slice it, my audio will NOT sync. I get this with ANY vhs tape I capture.
quote]

See my how to guide to sort gradual sync. http://www.vcdhelp.com/forum/userguides/140540.php
Although you can capture other sources in sync and i specifically blame the soundcard in the guide, this will also help you sync your VHS captures.

[rbermude]

I am relatively a "newbie" in DVDHelp.

I have a digi8camcorder.
I have no video or audio problems when I capture files in "avi" format. However, when I capture directly as mpeg2, I obtain the metalic noise that you describe.
So, my short term solution is to keep capturing in "avi", since the convertion to DVD works just fine.

However, since my digi8 camcorder supports playing my
old analog 8mm tapes, when I capture videos from
analog tapes, I get distored audio after 1 or 2
minutes of playback, even when I captured them as
"avi" files.

Have you experienced this problem, and what has been
your solution?

Rene