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PGGB upsampling software
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Old 28th August 2021, 09:05 AM   #11
MarcelvdG is offline MarcelvdG  Netherlands
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Exactly. If you would mute the output until the filter is completely filled, you would miss the first 11 seconds.
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Old 28th August 2021, 12:47 PM   #12
raptorlightning is offline raptorlightning  United States
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Quote:
Originally Posted by MarcelvdG View Post
Exactly. If you would mute the output until the filter is completely filled, you would miss the first 11 seconds.
If you can just buffer the whole file and keep the buffer filled, this becomes a non-issue, of course. I was thinking in regards to limited input bandwidth. Even with streaming (modern, not CD transport), there's buffering happening.
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Old 28th August 2021, 01:37 PM   #13
Hans Polak is offline Hans Polak  Netherlands
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Quote:
Originally Posted by MarcelvdG View Post
Exactly. If you would mute the output until the filter is completely filled, you would miss the first 11 seconds.
Yes, true as always. Think of it as if the file was preceded by 11seconds undithered silence.

Hans
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Old 28th August 2021, 02:17 PM   #14
Ken Newton is offline Ken Newton  United States
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Default ZB's speaks about PGGB-RT latency

I received the below email from ZB this morning. It regards our thread discussion on the PGGB-RT playback latency.
================================================

I saw some questions raised regarding tap length and delays and feasibility of doing the upsampling (or downsampling) in real-time.

The tap lengths are the maximum PGGB will use but they are not used all the time if the length of the track is not long enough. The taps are for the output rate. So choosing 2M and setting an output rate of 88.2kHz implies a maximum of 2M taps would be used at 88.2kHz and the track length has to be longer than or equal to 2M at the output rate, else the number of taps used will be reduced. If 1B taps are chosen, you need a very very long track. More here: PGGB - FAQ

I mention PGGB-RT is 'near real-time', this is because, in reality, it is doing exactly what the offline upsampling is doing except using memory not disk. It reads in a whole track into memory, does the upsampling and spits out the whole track into memory. It does not work like a typical DSP which has to wait in real-time to collect the necessary samples and then process, this would cause too much delay. For this reason, in foobar PGGB does not appear as a DSP but rather as a decoder under 'tools'.

So the real delay is the time taken to process the first track and this is possible because PGGB-RT always has access to whole tracks on disk. The results are the same as what you have already seen with the offline PGGB upsampled files.

When you have a playlist in foobar and hit play, there will be a delay equal to what it takes to process the first track, but this delay depends both on length of the track and also the CPU speed, generally a few seconds to a few 10 seconds. I use Intel IPP and also make use of multiple cores so the computation is quite efficient. While the first track is playing, PGGB-RT will start processing the second track so by the time the first track is done playing, the second track is already processed and is in memory, ready to be played.

Though streaming is not currently supported, most streaming apps have access to full tracks (at least for Qobuz and Tidal), so the same concept can be applied there too.

Regards,
-ZB

Last edited by Ken Newton; 28th August 2021 at 02:26 PM.
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