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Convolver DSP plug-in for Windows Media Player 10 - Page 5

post #121 of 326
It's been said before:
MCE is for people who wants it easy and doesn't require the top notch performance.
Sad but true.

post #122 of 326
Thread Starter 
Sure, but you could presumably write your own filter just as NVIDIA, Intervideo et al have done and add the sound processing in there. (Perhaps even some of the DScalers already done this.)
post #123 of 326
Since you can use TheaterTek in MCE, couldn't you allow TheaterTek to add in the FFdshow filters, of which one could be the convolver filter? I haven't tried this myself, but always assumed it would work. I would really like to know since I own MCE05 and would like to use FFdshow in the process. Up to this point, I've been concentrating on other areas of the HTPC, so I haven't downloaded TT to try it yet.
post #124 of 326
Thread Starter 
TT contains an NVIDIA decoder and so I suspect that MCE uses that, rather than TT itself. (This is based on speculation, rather than direct experimentation.)
post #125 of 326
TT can be used in mce thanks to a software called mymovies.

you could presumably write your own filter just as NVIDIA, Intervideo et al have done and add the sound processing in there

yep good luck
post #126 of 326
Thread Starter 
But mymovies effectively pushes MCE out of the way and runs TT?

Rolling your own, is indeed, as your smiley suggests, a bit of a tall order...
post #127 of 326
Thread Starter 
convolver 2.12 is now up on http://convolver.sf.net

This now contains the first version of ConvolverFilter which provides an alternative, but functionally equivalent, DirectShow filter to ConvolverWrapper.

This now shows up as a DXFilter in applications such as Adobe Audition.

post #128 of 326
Thread Starter 
and 2.13 ...

Automatic zero padding of filter lengths for optimal FFTW performance

The distribution package registers ConvolverFilter

I've also added ConvolverFilter.filterdata and ConvolverWrapperDMO.filterdata files for Zoom Player Pro

2.14 corrects a bug introduced in 2.12 that stopped the plug-in from functioning
post #129 of 326
You are a fast programmer.......

post #130 of 326
Thread Starter 
Quick poll:

I note that many of the impulse response freely available on the net are stereo wavs. At present, convolver only accepts mono impulse response files (which are applied to the sum of 1 or more input channels) and the results summed to produce the output channels specified in the config file.

To add a little more flexibility (and save having to split the stereo wavs) I propose to add to the config file a line after each impulse response filename specifying which channel should be take from that impulse response file.

I realise that this will be just extra clutter for those generating their (mono) impulse respone files using DRC, but I think that it may, on balance, be worth it.
post #131 of 326
Sounds like a good idea.

post #132 of 326
Hello John,

If I undestood correctly, using mono impulse responses will still be possible. Then I think that the new option is fine.
post #133 of 326
Thread Starter 
Yes, mono would still be possible, but you would have to add a 0 on a new line afer each filter filename to say "take the first channel".

(I realise that this is not v elegant, but I am reluctant to spend a lot of time on building a smarter config file parser when I hope to replace the config file with a user interface when the basic architecture is stable.)
post #134 of 326
That's OK for me. It's very clear, and adds possibilities.
post #135 of 326
Wouldnt a floating-point IR file format be better suited that a fixed-point wav file?

post #136 of 326
Sure, but you can use them if you want, or even floating point wavs (I'm using that right now).
post #137 of 326
Thread Starter 
That's right. Any libsndfile-compatible format is acceptable for Impulse Responses, with the proviso that raw .pcm or .PCM files are interpreted as 32-bit mono floats.
post #138 of 326
Thread Starter 
Convolver 2.15 is now up on http://convolver.sf.net

This allows multi-channel filter files to be used (specifying which channel is to be used for a filter path through the config file) -- so you can use all those stereo impulse files available on the internet, for example. Note that existing config files with mono filters will need to be edited to add a single line containing 0 after each filter file name.

It also allows tuning rigour to be set through the properties page.

Negative scaling factors are allowed (which will result in phase inversion). For straight inversion, don't use -0.0 for channel 0; use -0.99999 instead.

There has also been a good deal of internal refactoring and cleaning up for future optimization (so I would be particularly grateful for those interested in giving convolver a thrashing, as the testing needs to be much more extensive).

As ever, feedback welcome. In particular, I have been considering putting on a windows interface to replace the config text file approach.

Other feedback that I have had suggests, however, that the text file approach is straightforward even for the inexperienced, with the consequence that I would be better spending my time on

- making the config file parser more robust / helpful in its error messages and concentrating on features such as

- delay (not clear what that means yet), and

- the ability to select different configs automatically, depending on the input sample rate / channel numbers

for example.

The windows interface would be quite a lot of work and it is not clear that it would make convolver much easier to grasp (essentially because for each filter path you still need to specify

- the input channels and scaling factors to be applied to them;

- the impulse response file that is to be used (and which channel from that file)

- and the output channels are to receive the output (again with scaling factors, and the assumption that the outputs from different filter paths to a particular channel are summed)

I don't really want to spend time on the interface until convolver is feature complete.

However, I am open to persuasion about priorities.
post #139 of 326
So, what is the currently prefered method for generating impulse response files? From the work I've done in the past, the simplest method was using the tools in ACXO. Is the file output from this useful here?


post #140 of 326
Thread Starter 

Check out www.duffroomcorrection.com which has pointers to methods both for cross-over generation and impulse response generation.

ACXO output should be usable, as should rec_imp (http://www.duffroomcorrection.com/wi...Measuring_Tool)
post #141 of 326
Ed's been helping me with his rec_imp app - he compiled the Win32 version because I pestered him endlessly

But it just errors on my PC. I tried uninstalling ASIO4ALL (not using it anyway), but that didn't help.

Please post here if you have any more luck.
post #142 of 326
Originally Posted by Mark_A_W View Post

Ed's been helping me with his rec_imp app - he compiled the Win32 version because I pestered him endlessly

But it just errors on my PC. I tried uninstalling ASIO4ALL (not using it anyway), but that didn't help.

Please post here if you have any more luck.

Actually I have the same problem with rec_imp. I run XP SP2 and have a e-mu 1820M. It produces a error the moment I run it.
Both with asio and wdm drivers.
post #143 of 326
Yup, me too, that's why I ask. I'll try out ACXO and see how that works. Thanks guys.

post #144 of 326
Thread Starter 
I've had a go at compiling up rec_imp and there are indeed problems with the RTAudio library that it uses. I will pop a version that uses only DirectSound in with 2.16, which will contain some smalll optimizations, unless someone comes up with some show-breaking bugs with 2.15.
post #145 of 326
Thread Starter 
2.16 is now up on http://convolver.sf.net

It contains some internal optimizations over 2.15

2.16i is compiled with the Intel C++ compiler, 2.16 with the VC++ 2003. The former *may* be faster if you have a newer CPU. I'd be interested in hearing reports of any differences that you find.

I attach a DirectSound version of rec_imp (no ASIO support) for generating impulse response files. See http://www.duffroomcorrection.com/wi...Measuring_Tool for more details. No guarantees. The RtAudio library still seems to contain some bugs, but it works for me on a couple of different machines. I'll do a little more work on this, so feedback would be welcome.


rec_imp.zip 136.2021484375k . file
post #146 of 326
Thread Starter 
I've compiled up separate DS and ASIO versions of rec_imp and put them on http://www.duffroomcorrection.com/wi...Measuring_Tool

The ASIO version is still flakey, but see how you get on.
post #147 of 326
Thread Starter 
Coming soon: I am adding the capability to specify a list of filter paths (ie, a list of config files) which will be tested in turn and the first to match the input stream (no of channels, sample rate) will be used.

I am hoping that this will make Convolver more usable with, eg, DVDs where the source format can change from stereo to 5.1 and back again on some DVDs.

I will also try to allow the specification of filter paths that by-pass convolutiuon.

For those of you that have managed to get something usable working, it would be helpful to make a contribution either here or on http://www.duffroomcorrection.com/wi...Player_plug-in (so that others can learn from our experience) setting out your filters (and how you generated them), configuration files and equipment.

Equally, you might want to highlight any show-stopping usablity features (including complexity, I know).
post #148 of 326
I am really enjoying experimenting with jpravel's Convolver - thanks so much for all the hard work.

I followed Jones_Rush's guide - complicated but it works - I have not tweaked much but i get noticable results. I am now trying to use the newly compiled rec_impDS (the old version did not run on my MCE2k m/c).

My question is - if I use rec_imp, can I feed the output into DRC and then use the resulting file as a filter without converting to Wav (per the jones_rush guide)? i.e. use the impulse response PCM file directly in convolver?

I am thinking the following commands to build a do-it-all batch file:

1. rec_imp (with arguments)

2. Use the resulting file as input file in DRC

3. Use the resulting pcm as input file for Convolver

Am I missing a conversion here? I think that if I run this once for left, once for right it should work.

I am trying to build a batch file which run all of this for me automatically - if someone else has this working, please would you post your batch file so I can compare?

Thanks everyone!!
post #149 of 326
Dear jrpavel,

I was wondering if the convolver plug-in could be used even getting AC-3/DTS streams as output.

Today we are plenty of HW and SW solution (motherboards, audiocards, ffdshow, ac3filter) which are able to encode audio streams in AC-3 or DTS.
Thus I was wondering if the convolver plug-in could be used after AC-3/DTS decoding (performed for example by TT2.2 or ffdshow) and before AC-3/DTS encoding.

For example inserting it in ffdshow audio filters will help to perform almost all kind of operation with movies audio: today ffdshow only lacks of a powerful convolver!
post #150 of 326
Thread Starter 
Thanks for the feedback, and glad that you have got rec_imp working on your setup.

Convolver is able to read .pcm files, interpreting them essentially as a sequence of 32-bit floats, which means that they can provide an impulse only for a single channel / filter path.

This means that if you are using stereo, or multi-channel, you will need a series of .pcm files to do the job (as you correctly surmise).

There are different schools of thought about how best to do this. Eg for a stereo setup:

i) record mono impulses from each speaker separately and apply them to the corresponding channel -- the method that you are outlining;

ii) record stereo impulses L-LR and R-LR and apply the sum of convolved L-L and R-L to the left channel, and of convolving L-R and R-R with the right channel. (See http://www.ramsete.com/aurora/waveconv.htm for a schematic diagram)

Let us know how you get on.
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