24 Aug
2010
24 Aug
'10
10:23 a.m.
Hello all,
I've uploaded a new tutorial to YouTube:
http://www.youtube.com/watch?v=pnAqk054g7E
So using sidechain compression in Qtractor with the SC3 LADSPA plugin.
Concerning screencasting, anybody any experience with this? For this
tutorial I used recordMyDesktop, but it captures video to Theora, so
after editing and uploading the quality degrades considerably. The big
advantage of recordMyDesktop though is that it has JACK support and that
the overhead is pretty small so I can still run my setup at a decent
latency.
I've also started playing around with FFmpeg. The video quality is
waaaaay better if you capture to a lossless format but I'm having my
thoughts on the audio part. I compiled FFmpeg myself with libjack-dev so
it has JACK support. But FFmpeg apparently has troubles to keep up with
latencies below 20ms, lots of xruns on the FFmpeg side (JACK doesn't
complain though). And I have the feeling FFmpeg lags on the audio side.
So I'm thinking about capturing the video part with ffmpeg and the audio
part with jack_capture and mux the stuff later. But if anyone has any
other suggestions, let me know.
Best,
Jeremy
24 Aug
24 Aug
10:33 a.m.
What do you edit Theora with?
On Tue, Aug 24, 2010 at 12:22 PM, Jeremy Jongepier <jeremy(a)autostatic.com>wrote;wrote:
Hello all,
I've uploaded a new tutorial to YouTube:
http://www.youtube.com/watch?v=pnAqk054g7E
So using sidechain compression in Qtractor with the SC3 LADSPA plugin.
Concerning screencasting, anybody any experience with this? For this
tutorial I used recordMyDesktop, but it captures video to Theora, so after
editing and uploading the quality degrades considerably. The big advantage
of recordMyDesktop though is that it has JACK support and that the overhead
is pretty small so I can still run my setup at a decent latency.
I've also started playing around with FFmpeg. The video quality is waaaaay
better if you capture to a lossless format but I'm having my thoughts on the
audio part. I compiled FFmpeg myself with libjack-dev so it has JACK
support. But FFmpeg apparently has troubles to keep up with latencies below
20ms, lots of xruns on the FFmpeg side (JACK doesn't complain though). And I
have the feeling FFmpeg lags on the audio side.
So I'm thinking about capturing the video part with ffmpeg and the audio
part with jack_capture and mux the stuff later. But if anyone has any other
suggestions, let me know.
Best,
Jeremy
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--
Louigi Verona
http://www.louigiverona.ru/
11:01 a.m.
On 08/24/2010 10:33 AM, Louigi Verona wrote:
What do you edit Theora with?
Hello Louigi,
I've used OpenShot for the editing: http://www.openshotvideo.com/
Best,
Jeremy
1:34 p.m.
New subject: Tutorial on sidechain compression in Qtractor and a question about screencasting
Excerpts from Jeremy Jongepier's message of 2010-08-24 10:22:57 +0200:
Hello all,
I've uploaded a new tutorial to YouTube:
http://www.youtube.com/watch?v=pnAqk054g7E
So using sidechain compression in Qtractor with the SC3 LADSPA plugin.
Concerning screencasting, anybody any experience with this? For this
tutorial I used recordMyDesktop, but it captures video to Theora, so
after editing and uploading the quality degrades considerably. The big
advantage of recordMyDesktop though is that it has JACK support and that
the overhead is pretty small so I can still run my setup at a decent
latency.
I've also started playing around with FFmpeg. The video quality is
waaaaay better if you capture to a lossless format but I'm having my
thoughts on the audio part. I compiled FFmpeg myself with libjack-dev so
it has JACK support. But FFmpeg apparently has troubles to keep up with
latencies below 20ms, lots of xruns on the FFmpeg side (JACK doesn't
complain though). And I have the feeling FFmpeg lags on the audio side.
So I'm thinking about capturing the video part with ffmpeg and the audio
part with jack_capture and mux the stuff later. But if anyone has any
other suggestions, let me know.
Best,
Jeremy
Hi Jeremy.
I know little about screencasting, but I do know that recordmydesktop
can either encode on the fly or afterwards. Maybe it's possible to use
and convert its raw data, whatever format that may be, to something else?
The tutorial seems quite nice. I do have a little trouble with it
because you seem to have a really high resolution screen, and my biggest
screen has 1280x800. I'm also not sure it's a good thing that you can't
see the mouse, recordmydesktop has an option for that.
Seems to be quite a hassle to set sidechain compression up. The essence
being: know which sc3 port corresponds to what and what to route where.
I sadly couldn't get that from the video because of aforementioned
problems.
Regards,
--
Philipp
--
"Wir stehen selbst enttäuscht und sehn betroffen / Den Vorhang zu
und alle Fragen offen." Bertolt Brecht, Der gute Mensch von Sezuan
3:48 p.m.
New subject: Tutorial on sidechain compression in Qtractor and a question about screencasting
On 08/24/2010 01:34 PM, Philipp Überbacher wrote:
Excerpts from Jeremy Jongepier's message of
2010-08-24 10:22:57 +0200:
Hello Philipp,
Concerning the mouse, that's a noob move.
I'm using a 1920x1080 resolution, which is also the maximum YouTube HD
resolution and this should yield the best results:
http://www.google.com/support/youtube/bin/answer.py?hl=en&answer=132460
And the SC3 ports, I explain it in the video, the first two inputs of
the 3-channel Synth Duck track are for the stereo audio input you'd like
to compress and the third input is for the sidechain compression source,
in this case a kick from Hydrogen. For the outputs, 1 and 3 are the
compressed audio signals that I feed into the Synth Mix track.
I don't know where recordMyDesktop stores its raw/cache files, but afaik
I have encode on the fly disabled.
Jeremy
Hello all,
I've uploaded a new tutorial to YouTube:
http://www.youtube.com/watch?v=pnAqk054g7E
So using sidechain compression in Qtractor with the SC3 LADSPA plugin.
Concerning screencasting, anybody any experience with this? For this
tutorial I used recordMyDesktop, but it captures video to Theora, so
after editing and uploading the quality degrades considerably. The big
advantage of recordMyDesktop though is that it has JACK support and that
the overhead is pretty small so I can still run my setup at a decent
latency.
I've also started playing around with FFmpeg. The video quality is
waaaaay better if you capture to a lossless format but I'm having my
thoughts on the audio part. I compiled FFmpeg myself with libjack-dev so
it has JACK support. But FFmpeg apparently has troubles to keep up with
latencies below 20ms, lots of xruns on the FFmpeg side (JACK doesn't
complain though). And I have the feeling FFmpeg lags on the audio side.
So I'm thinking about capturing the video part with ffmpeg and the audio
part with jack_capture and mux the stuff later. But if anyone has any
other suggestions, let me know.
Best,
Jeremy
Hi Jeremy.
I know little about screencasting, but I do know that recordmydesktop
can either encode on the fly or afterwards. Maybe it's possible to use
and convert its raw data, whatever format that may be, to something else?
The tutorial seems quite nice. I do have a little trouble with it
because you seem to have a really high resolution screen, and my biggest
screen has 1280x800. I'm also not sure it's a good thing that you can't
see the mouse, recordmydesktop has an option for that.
Seems to be quite a hassle to set sidechain compression up. The essence
being: know which sc3 port corresponds to what and what to route where.
I sadly couldn't get that from the video because of aforementioned
problems.
Regards,
4:48 p.m.
New subject: Tutorial on sidechain compression in Qtractor and a question about screencasting
Excerpts from Jeremy Jongepier's message of 2010-08-24 15:09:12 +0200:
On 08/24/2010 01:34 PM, Philipp Überbacher wrote:
Ok, but on a much smaller screen it's hard to read/see things. It's hard
for me to see connections or which settings you used for the compressor.
Excerpts from Jeremy Jongepier's message of
2010-08-24 10:22:57 +0200:
Hello Philipp,
Concerning the mouse, that's a noob move.
I'm using a 1920x1080 resolution, which is also the maximum YouTube HD
resolution and this should yield the best results:
http://www.google.com/support/youtube/bin/answer.py?hl=en&answer=132460 Hello all,
I've uploaded a new tutorial to YouTube:
http://www.youtube.com/watch?v=pnAqk054g7E
So using sidechain compression in Qtractor with the SC3 LADSPA plugin.
Concerning screencasting, anybody any experience with this? For this
tutorial I used recordMyDesktop, but it captures video to Theora, so
after editing and uploading the quality degrades considerably. The big
advantage of recordMyDesktop though is that it has JACK support and that
the overhead is pretty small so I can still run my setup at a decent
latency.
I've also started playing around with FFmpeg. The video quality is
waaaaay better if you capture to a lossless format but I'm having my
thoughts on the audio part. I compiled FFmpeg myself with libjack-dev so
it has JACK support. But FFmpeg apparently has troubles to keep up with
latencies below 20ms, lots of xruns on the FFmpeg side (JACK doesn't
complain though). And I have the feeling FFmpeg lags on the audio side.
So I'm thinking about capturing the video part with ffmpeg and the audio
part with jack_capture and mux the stuff later. But if anyone has any
other suggestions, let me know.
Best,
Jeremy
Hi Jeremy.
I know little about screencasting, but I do know that recordmydesktop
can either encode on the fly or afterwards. Maybe it's possible to use
and convert its raw data, whatever format that may be, to something else?
The tutorial seems quite nice. I do have a little trouble with it
because you seem to have a really high resolution screen, and my biggest
screen has 1280x800. I'm also not sure it's a good thing that you can't
see the mouse, recordmydesktop has an option for that.
Seems to be quite a hassle to set sidechain compression up. The essence
being: know which sc3 port corresponds to what and what to route where.
I sadly couldn't get that from the video because of aforementioned
problems.
Regards, And the SC3 ports, I explain it in the video, the
first two inputs of
the 3-channel Synth Duck track are for the stereo audio input you'd like
to compress and the third input is for the sidechain compression source,
in this case a kick from Hydrogen.
For the outputs, 1 and 3 are the
compressed audio signals that I feed into the Synth Mix track.
Thanks Jeremy,
I managed to reproduce it with jack-rack, h2 and aeolus.
Yes, it's perverse to sidechain duck an organ, but I figured it would
provide a nice, constant sound, and thus be ideal for testing.
I had to enable 'create per-instrument outputs' in h2 to get the kicks
alone.
The routing in jack-rack is a bit funky.
in_1 is the sidechain input, in_2 the left and jack_rack_5655:sc3_1-1_i1
the right input.
So you hook up the h2 kick to in_1 and the signal to be ducked to the
next two ins.
You'll get the ducked signal left part from out_1 and right from out_2,
as you would expect.
The funky part is when the plugin is disabled though, in which case it
will route in_1 straight to out_1 and in_2 to out_2. If you go from
jack-rack straight to you speakers it results in the kick in the left
and the left signal in the right speaker.
Another thing worth mentioning with sc3 is that the 'chain balance'
parameter is most significant, you need to turn it up to hear any
ducking effect.
Thanks Jeremy, I wouldn't have bothered investigating without your video
:)
I don't know where recordMyDesktop stores its
raw/cache files, but afaik
I have encode on the fly disabled.
Jeremy
It should be possible to figure out where it stores the raw data. I don't
know how to convert it to whatever yt prefers.
Regards,
--
Philipp
--
"Wir stehen selbst enttäuscht und sehn betroffen / Den Vorhang zu
und alle Fragen offen." Bertolt Brecht, Der gute Mensch von Sezuan
25 Aug
25 Aug
10:30 a.m.
New subject: Tutorial on sidechain compression in Qtractor and a question about screencasting
On 08/24/2010 04:48 PM, Philipp Überbacher wrote:
Oh yeah, thanks for mentioning, I'll add that to the description too
because you need per-instrument outputs in Hydrogen.
recordMyDesktop stores its cache stuff in /tmp. Unfortunately the .tmp
it creates can't be read by any app I've tried (ffmpeg, mplayer etc.).
So I'm going to try ffmpeg with jack_capture.
Best,
Jeremy
Ok, but on a much smaller screen it's hard to read/see things. It's hard
for me to see connections or which settings you used for the compressor.
I agree, and I will post the settings of the compressor in the
description of the video. Concerning the JACK connections, I'm aware
that those can become illegible at lower resolutions. But then one can
ask the question, is that the uploader's fault or a limitation of YouTube?
And the SC3
ports, I explain it in the video, the first two inputs of
the 3-channel Synth Duck track are for the stereo audio input you'd like
to compress and the third input is for the sidechain compression source,
in this case a kick from Hydrogen.
For the outputs, 1 and 3 are the
compressed audio signals that I feed into the Synth Mix track.
Thanks Jeremy,
I managed to reproduce it with jack-rack, h2 and aeolus.
Yes, it's perverse to sidechain duck an organ, but I figured it would
provide a nice, constant sound, and thus be ideal for testing.
I had to enable 'create per-instrument outputs' in h2 to get the kicks
alone.
The routing in jack-rack is a bit funky.
in_1 is the sidechain input, in_2 the left and jack_rack_5655:sc3_1-1_i1
the right input.
So you hook up the h2 kick to in_1 and the signal to be ducked to the
next two ins.
You'll get the ducked signal left part from out_1 and right from out_2,
as you would expect.
The funky part is when the plugin is disabled though, in which case it
will route in_1 straight to out_1 and in_2 to out_2. If you go from
jack-rack straight to you speakers it results in the kick in the left
and the left signal in the right speaker.
That part confuses me too, the internal routing of the plugin.
Another thing worth mentioning with sc3 is that the
'chain balance'
parameter is most significant, you need to turn it up to hear any
ducking effect.
That's right, it has to be set to 1 otherwise it doesn't use the
sidechain signal:
http://plugin.org.uk/ladspa-swh/docs/ladspa-swh.html#id1427
Thanks Jeremy, I wouldn't have bothered
investigating without your video
:)
You're welcome. I like doing this stuff so hopefully more to come.
I don't know where recordMyDesktop stores its
raw/cache files, but afaik
I have encode on the fly disabled.
Jeremy
It should be possible to figure out where it stores the raw data. I don't
know how to convert it to whatever yt prefers.
4:06 p.m.
New subject: Tutorial on sidechain compression in Qtractor and a question about screencasting
Excerpts from Jeremy Jongepier's message of 2010-08-25 10:30:05 +0200:
Oh yeah, thanks for mentioning, I'll add that to the description too
because you need per-instrument outputs in Hydrogen.
I wrote to Steve Harris about it yesterday and in the meanwhile figured
out how to change the port order in the sc3 ladspa plugin. It was rather
trivial, no C knowledge required.
As far as I can see, sc2 and sc3 in both ladspa and lv2 variants are
affected. Are there any more swh plugins with that kind of problem?
Writing patches for those would only take minutes, but the question is
whether it should be done. It would require re-routing in projects that
use the affected plugins. A lot of hosts don't support plugins where the
number of in/out ports doesn't match or isn't 1/1 2/2, so I think there
aren't that many projects affected.
recordMyDesktop stores its cache stuff in /tmp. Unfortunately the .tmp
it creates can't be read by any app I've tried (ffmpeg, mplayer etc.).
So I'm going to try ffmpeg with jack_capture.
Best,
Jeremy --
Philipp
--
"Wir stehen selbst enttäuscht und sehn betroffen / Den Vorhang zu
und alle Fragen offen." Bertolt Brecht, Der gute Mensch von Sezuan
On 08/24/2010 04:48 PM, Philipp Überbacher wrote:
The question is what kind of display you assume those watching your
video have. It also depends on what you're showing. In a movie details
might not matter as much as in a tutorial.
Ok, but on a much smaller screen it's hard to read/see things. It's hard
for me to see connections or which settings you used for the compressor.
I agree, and I will post the settings of the compressor in the
description of the video. Concerning the JACK connections, I'm aware
that those can become illegible at lower resolutions. But then one can
ask the question, is that the uploader's fault or a limitation of YouTube? And the SC3 ports, I explain it in the video, the
first two inputs of
the 3-channel Synth Duck track are for the stereo audio input you'd like
to compress and the third input is for the sidechain compression source,
in this case a kick from Hydrogen.
For the outputs, 1 and 3 are the
compressed audio signals that I feed into the Synth Mix track.
Thanks Jeremy,
I managed to reproduce it with jack-rack, h2 and aeolus.
Yes, it's perverse to sidechain duck an organ, but I figured it would
provide a nice, constant sound, and thus be ideal for testing.
I had to enable 'create per-instrument outputs' in h2 to get the kicks
alone.
The routing in jack-rack is a bit funky.
in_1 is the sidechain input, in_2 the left and jack_rack_5655:sc3_1-1_i1
the right input.
So you hook up the h2 kick to in_1 and the signal to be ducked to the
next two ins.
You'll get the ducked signal left part from out_1 and right from out_2,
as you would expect.
The funky part is when the plugin is disabled though, in which case it
will route in_1 straight to out_1 and in_2 to out_2. If you go from
jack-rack straight to you speakers it results in the kick in the left
and the left signal in the right speaker.
That part confuses me too, the internal routing of the plugin. Another thing
worth mentioning with sc3 is that the 'chain balance'
parameter is most significant, you need to turn it up to hear any
ducking effect.
That's right, it has to be set to 1 otherwise it doesn't use the
sidechain signal:
http://plugin.org.uk/ladspa-swh/docs/ladspa-swh.html#id1427
Thanks Jeremy, I wouldn't have bothered
investigating without your video
:)
You're welcome. I like doing this stuff so hopefully more to come.
I don't know where recordMyDesktop stores its
raw/cache files, but afaik
I have encode on the fly disabled.
Jeremy
It should be possible to figure out where it stores the raw data. I don't
know how to convert it to whatever yt prefers.
5001
days inactive
5002
days old
linux-audio-user@lists.linuxaudio.org
7 comments
3 participants
participants (3)
-
Jeremy Jongepier -
Louigi Verona -
Philipp Überbacher