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Recorded a WAV file in Vegas fine, but playback (VLC, Win Media, etc) is way too fast

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John Romein
Recorded a WAV file in Vegas fine, but playback (VLC, Win Media, etc) is way too fast
on Aug 10, 2018 at 8:43:35 pm

Recorded thousands of WAV files using Vegas. Two weeks ago everything was fine. Now, Vegas records the WAV file fine. Even plays back on the timeline fine. I close Vegas on my capture computer. Then I try to play back the WAV file using anything else (VLC, Win Media Player, etc) and even loading the file onto Vegas on the same capture PC or on another PC....plays way too fast...like chipmunks! I figure that when the capture was close, Vegas must have updated some metadata incorrectly that makes the file play fast. Problably something simple.

Only thing that has changed on the capture PC, between when it worked and now, is that we powered it down for 10 days while we vacationed.


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Bouke Vahl
Re: Recorded a WAV file in Vegas fine, but playback (VLC, Win Media, etc) is way too fast
on Aug 11, 2018 at 7:40:38 am

What happens is that the playback software sees a sample rate that the recording was made on, and that value seems to be wrong. (it's just 4 bytes in the beginning of the file.)
So, if that value says the file is recorded at 48000, while it was in fact recorded at 24000, it will playback 48000 samples every second.
So, open with VLC or WaveAgent or Quicktime or whatever, and look at the sample rate. If that says something else than expected you know where to look for.
Now if this is indeed the case, not sure what can fix it without rendering, but I can write something simple to change the value. (But there 'must' be something out there that can do it. The whole operation for lots of files should take less than a second.)

Bouke
http://www.videotoolshed.com


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John Romein
Re: Recorded a WAV file in Vegas fine, but playback (VLC, Win Media, etc) is way too fast
on Aug 11, 2018 at 5:33:51 pm

We recorded the WAV files using 24bits and 96Khz. Both Mediainfo and VLC confirm the 96000 sample rate. Here's the Mediainfo report:

General
Complete name : ......\Track 2 - 1.wav
Format : Wave
File size : 3.08 MiB
Duration : 11 s 203 ms
Overall bit rate mode : Constant
Overall bit rate : 2 305 kb/s
Encoded date : 2018-08-10 12:17:33

Audio
Format : PCM
Format settings : Little / Signed
Codec ID : 1
Duration : 11 s 203 ms
Bit rate mode : Constant
Bit rate : 2 304 kb/s
Channel(s) : 1 channel
Sampling rate : 96.0 kHz
Bit depth : 24 bits
Stream size : 3.08 MiB (100%)


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Bouke Vahl
Re: Recorded a WAV file in Vegas fine, but playback (VLC, Win Media, etc) is way too fast
on Aug 11, 2018 at 9:41:23 pm

But, did you indeed record at 96000 Hz?
(the only ones who do so are very snobby extremely expensive studios, and technical people who do research.
Human hearing goes up to 20Khz tops, and that is for young people. My hearing stops at 10Khz. So it makes no sense to go over industry standard 48Khz.
If you did record at 96000, I have no clue.
For math, it's simple.
96000 samples per second * 3 bytes per sample / 1024 makes 281 Kb per second.
Your 11.2 file becomes 3.07 Mb
So far all is fine. Then there is a bit more in the file, the bitrate. But that is redundant for uncompressed as the math is very simple, so it is ignored by most players.

Iow, I'm clueless without seeing a file.

One other thing to try, you could use Audacity and tell it to import RAW. then fill in your values.
if that does not work, experiment. But if you have to fill in other values, your recording went bad.
(I can imagine, as 96Khz is not used often, not sure if your soundcard / capture system supports it well.)

Bouke
http://www.videotoolshed.com


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John Romein
Re: Recorded a WAV file in Vegas fine, but playback (VLC, Win Media, etc) is way too fast - SOLVED
on Aug 13, 2018 at 6:26:04 pm

Duh! Solved the problem. We use an Echo Layla24 box and card to import the audio. And the box does support 24 bit depth and 96KHz....we use this when our customers ask for it. Turns out that we had set the Echo software's clock option to "Spdif" for a DAT tape and not reset the clock back to "internal" for audio cassettes.

Maybe someone can explain how this impacts the way Vegas records the WAV files...especially since playing back the timeline played perfect, yet playing back the saved file did not play well...even though the MediaInfo parameters looked good?


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