I've to merge two (or more) audio files (like a guitar and a drum track) into a single file.
I'm running over linux CentOS and I'd need a command line tool to do so, because I've got to run this as part of a background process, triggered via crontab of a custom bash script.
I also need to be able to change the pan, volume, trim and start time (i.e I want the guitar track to start after 1.25ms after the drum track so that they can be both in sync with each other).
My first choice would be ffmpeg, but I was wondering if there could be something more specific, reliable and less fuzzy than ffmpeg.
thx a ton!
-k-
Sox is the best way to do this. Your command would be the following:
sox -M guitar.wav drum.wav final.wav
I don't know for sure if sox can do all that (esp start time), but I think so: http://sox.sourceforge.net/
Certainly it would be my "goto" tool for that, short of writing my own.
Related
My machine is running Ubuntu 20 LTS. I want to manipulate the input live audio in real-time. I have achieved pitch shifting using sox. The command being -
sox -t pulseaudio default -t pulseaudio null pitch +1000
and then routing the audio from "Monitor of Nullsink" .
What I actually want to do is, silence randomized parts of the input audio, with a range. What I mean is, randomly mute 1-2s of the input audio.
The final goal of this project will be to write a script that manipulates my voice and makes it seems like my network is bad.
There is no restriction in method of achieving. That is we may use any language, make an extension, directly manipulate the input audio with sox, ffmpeg etc. Anything goes.
Found the solution by using trim in sox. The project can be found in
https://github.com/TathagataRoy1278/Bad_Internet_Audio_Modulator
I've been playing around with some speech-to-text and text-to-speech systems, and am running into the problem that when the computer makes sounds that it can recognize, it starts taking commands from itself. To avoid this, I'd like a stream of all sounds picked up by the microphone that were not produced by the computer itself.
I see that PulseAudio has an echo cancellation module, but so far I have been unable to distinguish between its output and the raw microphone output: it still contains all the sounds picked up by the microphone that came from the computer speakers. I wonder if the default echo canceller is doing the opposite of what I want (i.e., it removes sounds heard by the microphone from being sent to the speakers).
Any idea how I can do this (preferably with pacmd)? I have thoroughly confused myself trying to specify non-default sources for the echo canceller, and have wandered into loopback modules and other things that are probably irrelevant. I know very little about PulseAudio, haven't found a good introduction to it (I've looked through much of the PulseAudio documentation but didn't see anything relevant), and might just be missing something simple. I feel frustrated that echo cancellation apparently doesn't work, I can't find documentation on it, and I can't find examples of it working from other people.
Thanks in advance for the help!
Other details that might be relevant: I'm running Ubuntu Saucy on a Lenovo Thinkpad T410. I'm using the built-in microphone and speakers (so, I'm pretty sure they're using the same sound card and I won't have clock drift issues). My actual application gets its sound through GStreamer, but GStreamer gets it from PulseAudio, and I don't think GStreamer itself has AEC capabilities. If there's a different way of doing this, I'd gladly switch to that.
Ah, I've got it! Merely loading the echo cancellation plugin isn't enough; you then need to start using it. In particular, it will only cancel echos of sounds passed into it, and if no sounds go through it, nothing will be cancelled. So, open /etc/pulse/default.pa and add the line
load-module module-echo-cancel
towards the bottom (I put it right after the line that loads module-filter-apply). Then, restart the PulseAudio daemon by running (as a non-root user) pulseaudio -k. Next, run pacmd to get a command line interface to PulseAudio, and give it the commands list-sources and list-sinks. Note the indices of the echo canceller in the responses. Edit /etc/pulse/default.pa again, and uncomment the two lines at the end about set-default, replacing the words input and output with the indices of the echo canceller's source and sink. Finally, restart PulseAudio again with pulseaudio -k (again, run as a non-root user).
Now, by default all sounds to be output get sent through the echo canceller before heading to the speakers, and all sounds to be input get pulled from the echo canceller after coming in through the microphone, and things actually work. You can verify that it's working by running pavucontrol and looking at the sound levels on the Input Devices screen (try playing some music and speaking, and note that the echo cancelled input shows normal sound levels when you speak but very low levels (verging on nothing) when you're silent but the music is playing).
This answer mostly comes from this post, which I wish I'd found weeks ago.
i still want to check my Bootloader + Linux Startupcode for an embedded device. Therefore i want to catch the time for every command printed to the serial port.
I know there are programs like putty (which i can dearly recommend), getty, cutecom, picocom, screen etc. But none of these add timestamps to the incomming messages on the host screen (I'm not really talking about the date, more like how many ms have gone since the first output). It actually sounds not like a big deal.
I found out there is one script doing what i wanted to have, called grabserial but it's not working properly, since it's to slow to process the whole output. I discussed this problem in a different forum (if you want to know: grabserial problem but it's not part of the topic). So i can't use that script.
Now again: can you tell me a terminal for Linux which adds timestamps to every line, which was received from a Serial Port?
Thank you
[Edit:] I've found a pretty rough workaround with cereal, which wants to have some settings, since it locks the port everytime you use it. In the end, it adds the actual date and time, not the startup time and difftime between each step, so as you can see I'm still looking for an adequate solution.
This might come 3 years too late, but minicom (https://en.wikipedia.org/wiki/Minicom) supports timestamps for every line printed on the terminal. In Ubuntu it's directly available in the default repos.
You might want to look in to using strace to monitor the serial port. See How can I monitor data on a serial port in Linux?
If you are willing to build the binary by yourself, you can try a branched picocom (https://github.com/codepox/picocom). This is based on picocom 1.7 which is a little old.
I have forked and enhanced this picocom and made it be able to show either delta-time or wall-clock timestamp. You can find it here (https://github.com/tdwong/picocom-with-timestamp). You still have to build the binary by yourself.
Here is how I use it. Note, N is the command to enable/toggle timestamp.
$ picocom -b 115200 /dev/ttyUSB0
...
<ctrl-a> N # enable delta-time timestamp
<ctrl-a> N # toggle wall-clock timestamp
<ctrl-a> N # disable timestamp
tio found at https://tio.github.io provides various timestamp options:
-t, --timestamp
Enable line timestamp.
--timestamp-format <format>
Set timestamp format to any of the following timestamp formats:
24hour 24-hour format ("hh:mm:ss.sss")
24hour-start 24-hour format relative to start time
24hour-delta 24-hour format relative to previous timestamp
iso8601 ISO8601 format ("YYYY-MM-DDThh:mm:ss.sss")
Default format is 24hour
In your case, showing how much time has passed since start, that would be something like this:
tio -t --timestamp-format 24hour-start /dev/ttyUSB0
Settings can also be enabled in tio configuration file ~/.tioconfig
I believe that ExtraPuTTY is the solution you are looking for.
However, I wasn't clear if you wanted something to run ON Linux or just to be able to monitor it (SSH to Linux). If you didn't want a Windows solution, then I apologize.
May you tell me how can I control the timing of the movie made of many data files please? It is going so fast that looks weird. I want to make it slow so that I could see the complete pattern.
Thank you for your time.
Update: I am using: ffmpeg -f image2 -r 10 -i %d.gif video2.mpg
But it gives an error and gives out no output.
You can use the Win32 Sleep() function to pause for a few milliseconds between frames/plots/data files.
Update: You didn't mention ffmpeg originally, so I thought you were developing your
own C++ playback code. It appears you're trying to build and execute a ffmpeg command from inside your C++ code, instead. According to the ffmpeg documentation, the -r option controls the frame rate, so just lower it if you want the playback to be slower.
You may need to specify all the GIF file names (via multiple -i filename options) in a single ffmpeg command.
How can the linux frame buffer, on Cell Linux, be captured to obtain either screen shots or movies?
Is there a tool to do this for a running program, or must the program writing to, and presumably controlling, the frame buffer also handle capture and recording? If so, how would the program do so?
Many tools for doing so, for example FBGrab and fbdump; look at the sources for those two, it would be pretty easy to extend either one or write your own which captures video instead of just snapshots.
However, I would recommend that the program writing to the framebuffer be the one recording as well, in order to synchronize capturing frames between writing them (and not partially through a write, or skipping, or ...)
you could use ffmpeg or avconv (eg. avconv -f fbdev -i /dev/fb0 mymovie.flv).