Linux-audio-user August 2013

linux-audio-user@lists.linuxaudio.org

86 participants
78 discussions

by J. Liles

As some of you may recall, every time I've posted a demo video to LAD, I've had to include a disclaimer excusing the poor quality due to a lack of functional screencasting tools. Well, it took a couple of weeks of hair pulling and many, many hours of testing, but I finally arrived at a solution. Anyone who wants to create a screencast and record audio via JACK *in perfect sync* must do the following: Get ffmpeg. Apply this patch to it: https://github.com/original-male/FFmpeg/commit/d02509d04d396a98646ca81e9ba3… Build it with vorbis and h264 support. Then, start your favorite desktop environment. I use Xephyr for this. Have jack running (at -r 48000) Then run the following command: ffmpeg -fflags +genpts+igndts -f x11grab -vsync 0 -r 30 -s 1920x1080 -i :${DISPLAY}.+0,0 -vcodec h264 -f jack -ac 2 -r:a 48000 -i screencast -acodec pcm_s16le -r:v 30 -vsync 2 -async 1 -map 0:0,1,0 -map 1:0 -preset ultrafast -qp 0 "$FILE" Where DISPLAY is the number of your X11 display and FILE is the filename for the screencast. I use a .mkv extension for the matroska container. Remember to connect the streams you want recorded to the 'screencast' JACK inputs! With this setup I'm able to record a full 30 FPS @ 1080P with audio in perfect sync. Please share your results too. With some more evidence I might have a good case to get ffmpeg to accept my patch. Enjoy!

11 years, 11 months

Decompressor for linux?

by Ken Restivo

It's been a while since I did anything with linux audio, or even had much to do with music, but now I'm attempting to listen to music that has been recently released, and find it unlistenable. The mastering! The compression! It burns!! It burns!!! Auugh, my ears!! I mean, it's obviously distorted. I can hear the clipping. People are putting out released tracks that I can't listen to without getting a splitting headache. Is there any such thing that I might be able to pipe into an ALSA or JACK setup, which would repair these broken tracks? It's sad. It's like people are mastering for laptop speakers, cellphone speakers, or earbuds, and nothing else. FWIW, as an example, I've just stumbled across the music of Amanda Palmer, downloaded her latest album, I think the music is great, or could be, but I can't listen to it because of the mastering. -ken

11 years, 11 months

Re: [LAU] sortof OT -- ART tube pac preamp and compressor noisy?

by Fons Adriaensen

On Mon, Aug 12, 2013 at 08:24:41AM -0700, Rusty Perez wrote: > The preamp does not use an external power suplly transformer cube. It > is connected to the power with a grounded cable. Of course. But if the internal power supply isn't OK it will generate hum. > It goes via xlr to one of the inputs on my delta 1010lt card. > Both computer and preamp are connected to the same power source. You need to be more specific, nobody can help you otherwise. The delta 1010lt has two mic inputs with XLR connectors. Is it one of these you are using ? It is probably configured for maximum gain and you need to change that. It's done using jumpers on the card, see page 8 of the manual. First try the setting marked '2A' in the manual. If you can't get enough signal (by increasing the gain on the preamp) with that, try '2'. If still not enough, try '1A'. Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow)

11 years, 11 months

Reverse reverb how-to with LV2 plugin

by Sam Tuke

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Hi all, First post here. I wrote a new blog entry yesterday: "Achieve reverse reverb (echo) effect with GNU/Linux audio plugins" https://blogs.fsfe.org/samtuke/?p=599 I used Qtractor and IR.LV2 to recreate an effect like one applied to pianos by the famous electro group Justice. It might be of interest to some of you. Best, Sam. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.13 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iF4EAREIAAYFAlII7o8ACgkQ1bR1Itj7YQVreQD+PIlYFfeT7lDYGxOiA0Cc3Y9P M9gC92WTZ7iBPWDC24IA/Rsddcb/XsTx9rYX0K9/77c3qpc1AVrvC3OTFmy5l3LD =WuoC -----END PGP SIGNATURE-----

11 years, 11 months

[Music] Two little tracks

by Florian Paul Schmidt

Hi, getting back into Renoise a bit lately. So here's two rough cuts. One is more experimental than the other :D https://soundcloud.com/fps-2/check-refrac https://soundcloud.com/fps-2/whence Have fun, Flo

11 years, 11 months

Wires for Empathy Trailer Release (Tube Open Source Video Project)

by Thomas Vecchione

So the Tube project has been chugging along in the background and a new trailer has been released... http://urchn.org/post/wires-for-empathy-trailer All the sounds were recorded on a Tascam DR-40 with a small variety of mics (Built In Mics for a surprising amount, SM57s, and AKG c451/ck94 on a jury rig for a M/S combo). Everything with one exception was done on Linux with Ardour3.3, or git versions near that, the exception being cleaning up the audio (Noise reduction primarily) which sad fact of life is that there isn't much on Linux to compare to even basic tools on Mac or Windows sadly, but will comment more on that some other time. Many thanks to Robin Gaerus for putting up with me over the past couple weeks as I broke and he fixed his wonderful work on the Video Timeline of course:) Seablade

11 years, 11 months

Soviet Classical Radio Stream

by Patrick Shirkey

Hi, Some of you might be interested in a radio stream with Soviet Era Classical. Excellent production quality from that bygone era. All audio digitised and professionally restored using Linux Audio Tools of course. You can access the stream and others from the community directly in your browser via the Radio Station link at http://linux-audio.com. For those of you have text based (no js) interfaces or prefer to use their own player there's a direct link at this site: http://lowcostrestaurantmusic.com It's not a very powerful server but I am interested to see what kind of load it can tolerate. If you notice any glitches or have any other feedback about the selection please let me know. -- Patrick Shirkey Boost Hardware Ltd

11 years, 11 months

Unusual error message when recording

by Kevin Utter

Hi all! I haven't seen this error before, and don't know what it means: subgraph starting at a2j timed out (subgraph_wait_fd=19, status = 0, state = Finished, pollret = 0 revents = 0x0) This occurred when recording the audio from a softsynth played by a MIDI sequence. Applications were: MIDISH, setBfree, Nama, Jackd, and A2JMIDID. It occurs consistently after aprox. 20-25 seconds. A similar error occurs when recording no audio from Jack with Nama: subgraph starting at Nama timed out (subgraph_wait_fd=17, status = 0, state = Running, pollret = 0 revents = 0x0) This is without MIDISH or setBfree. At the same time, Nama responds: **** alsa_pcm: xrun of at least 2.411 msecs zombified - calling shutdown handler At which point Nama has to be stopped with Ctrl-C. This occurs with and without lightdm (desktop manager) running. I'm currently running Jack 1. Previously when running Jack 2, I would get XRuns at the same 20-25 second interval, but recording would continue. I had thought that perhaps the error might be caused because my whole operating system is on a USB disc, in order to keep the rest of the system unchanged, but is this the type of error I would expect in a situation where audio file writing to a perhaps slow disc would give, or is this something else? I probably need to reconsider running from a USB disc, but I wasn't quite ready to play with re-partitioning Windows discs, and playing with dual boot situations yet, although it is still perhaps a better idea. Sorry to be so verbose, but wanted to be thorough. Thanks for any help or suggestions. Kevin

11 years, 11 months

Re: [LAU] Using a USB pedalboard to trigger keystrokes

by Jeff Sandys

I would use one of the Python midi classes to read the midi input and fire the commandline. No soldering required, just a little Python script. http://wiki.python.org/moin/PythonInMusic -- Jeff Sandys Julian said: Hello everyone! Someone told me, that they were intending to get a pedalboard to trigger keystrokes to control some commandline applications. And I've been wondering. ...

11 years, 11 months

Re: [LAU] alsaplayer error using USB Audio DAC

by Len Ovens

On Thu, August 8, 2013 4:10 am, Roger Weinheimer wrote: > **** List of PLAYBACK Hardware Devices **** > card 0: SoundByLayout [SoundByLayout], device 0: Master [] > Subdevices: 1/1 > Subdevice #0: subdevice #0 > card 1: default [USB Audio DAC ], device 0: USB Audio [USB Audio] > Subdevices: 1/1 > Subdevice #0: subdevice #0 > **** List of CAPTURE Hardware Devices **** > card 0: SoundByLayout [SoundByLayout], device 0: Master [] > Subdevices: 1/1 > Subdevice #0: subdevice #0 Ok, going back to your original post :) You do show both cards, good. Your USB card is playback only, but that is what you are trying to do, so that is ok. The portion of /var/lib/alsa/asound.state that you show is for the internal card. That may mean your USB card has no controls which is ok, it just means volume can only be changed at the card or is always "100%". I find alsamixer easiest to use to check that. You used a commandline of: alsaplayer /path/filename.flac Generally for trouble shooting I would hit the card directly: alsaplayer -i hw:1,0 filename.flac aplay --device=hw:1,0 filename.flac may still get errors -- Len Ovens www.OvenWerks.net

11 years, 11 months

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Linux-audio-user August 2013