Increased playback speed after encoding multichannel to stereo

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ilk2011
Posts: 30
Joined: Tue Feb 11, 2020 7:20 pm

Increased playback speed after encoding multichannel to stereo

Post by ilk2011 »

Direct encoding any multichannel source (*.pcm, *.dts) to stereo/joint stereo *.mp3 results in increasing playback speed. Looks like three times faster in case of 5.1 channels to stereo. Older versions and the current one.
admin
Site Admin
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Joined: Wed Nov 17, 2010 12:56 pm

Re: Increased playback speed after encoding multichannel to stereo

Post by admin »

I cannot reproduce the issue. Are you using the latest (1.104) version from https://xrecode.com?
If so, please send the Diagnostic information (it's under About button) to xrecode@gmail.com
It would be nice if you could share the source multi-channel file as well (via https://wetransfer.com/ or other service) to xrecode@gmail.com.
ilk2011
Posts: 30
Joined: Tue Feb 11, 2020 7:20 pm

Re: Increased playback speed after encoding multichannel to stereo

Post by ilk2011 »

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admin
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Re: Increased playback speed after encoding multichannel to stereo

Post by admin »

ilk2011
Posts: 30
Joined: Tue Feb 11, 2020 7:20 pm

Re: Increased playback speed after encoding multichannel to stereo

Post by ilk2011 »

So far encoding from *.dts and *.wav shows correct playback speed. Tomorrow I'll try with 4.0 and 5.0 tracks and report results.
ilk2011
Posts: 30
Joined: Tue Feb 11, 2020 7:20 pm

Re: Increased playback speed after encoding multichannel to stereo

Post by ilk2011 »

It looks fine with other input files, but... Please, check the duration of input and output files. I can't estimate the difference by ear, but MediaInfo gives different values for input and output files, see picture.
Image
admin
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Re: Increased playback speed after encoding multichannel to stereo

Post by admin »

I don't really know. When you convert that mp3 to wav, you will get exactly 20 s 00 ms duration.
ilk2011
Posts: 30
Joined: Tue Feb 11, 2020 7:20 pm

Re: Increased playback speed after encoding multichannel to stereo

Post by ilk2011 »

Maybe that's correct for backward encoding. But I tried one more file PCM 96KHz-24bit-5.1 → MP3 48KHz-8bit-2.0 (joint stereo) to encode. The result is the same - different duration (see picture). The difference is hundredths of a second, but still. It might be audible for piano recordings and visible for the whole album/concert.
Image
admin
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Re: Increased playback speed after encoding multichannel to stereo

Post by admin »

I don't know what exactly is going on here, but I converted that 5.1 wav file to wav 2.0 (duration in Mediainfo 20:00) and then manually converted it to 320/CBR mp3 via lame.exe and duration shown by MediaInfo was also 20:40.
ilk2011
Posts: 30
Joined: Tue Feb 11, 2020 7:20 pm

Re: Increased playback speed after encoding multichannel to stereo

Post by ilk2011 »

I don't know also.
One more attempt today: DTS HD Master Audio file 96-24-5.0 (duration 01min 18,190) direct convert to mp3 320 CBR joint stereo gives output file with duration 01 min 18,960.
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