Convert Stereo To Mono
Sacha Weakland
Thank you, Marillion - the right-click and choose combine was EXACTLY what I needed (as my stereo audio was off center and slightly different quality). The "combine" option did just that, and had no phasing issues.
Thanks, again!!
I use the FFmpeg library for a personnal project and I need help about one thing. I have a music file in stereo sound and I want to convert this stereo sound to mono sound ? Is it possible with this library ? Is there a function inside to do this job ? My project is in C/C++.
After you encoded the frame, and have done the things you have to do, your data buffer will be filled with the audio. Now it depends how your format is (see here) and how many channels you have. Let's assume it is signed 16bit stereo, than your buffer would look like:
I have a bunch of stereo MP3s I'd like to convert to mono. What is the best way to do this? I would prefer something that would let be batch process them. I want to keep the quality as close to the original as possible. My files are also in different bitrates, so I don't want to make all files 320kpbs when some are only 128.
Converting from stereo to mono will mean re-encoding, so keeping the same bit rate would be meaningless. In fact, converting a 128 kbit/s MP3 -> a new 128 kbit/s MP3 will net you godawfully terrible quality, even if the second one is mono (and therefore requires a lower bit rate for the same subjective quality).
Generally, I would use a Variable Bit Rate (VBR) setting for MP3, which targets a specific quality and lets the encoder set whatever bit rate is required (completely silent audio needs a lower bit rate than whalesong, which needs a lower bit rate than dubstep). From the command-line, ffmpeg can convert audio to mono with the option -ac 1, like so:
See this page for a guide to using -q:a. Note that the table on that page is aimed at stereo audio; the actual bit rates you'll see will be somewhat lower. Normally, I recommend 3-4, but since you're encoding from MP3s rather than an original CD, you should aim a bit higher.
That makes no sense. Turning the source clip to stereo is easy in MC(clip-modify-set multichannel audio). Changing a clip already in the timeline from dual mono into stereo (maintaining clip levels etc.) is what cannot be done. Export/import won't solve that.
A better work around than this would be to select that section in the timeline and create an Audio mixdown to sequence, choose stereo. It will place the clips on a new or existing stereo track, some position in the timeline. If you had any effects, you could save those effects into a bin, then remove them before doing the mixdown and re-applying after.
Thank you.
Yes, I do those two steps. And then I have a single mono track.
So, next I want to now convert that mono track to a stereo track with duplicate sounds.
But I have no options to do so available in the drop down menu. They are all grayed out.
Ok.
So, the project will have two tracks. One mono track with voiceovers, and one stereo track with music.
When I save this as a WAV file, the tracks will be combined into a stereo recording, with the voice in both channels?
Thanks
So, the project will have two tracks. One mono track with voiceovers, and one stereo track with music.
When I save this as a WAV file, the tracks will be combined into a stereo recording, with the voice in both channels?
There are indeed rare instances of recordings in which the L&R channels are in opposite phase. This was done in the late 70s and early 80s to create a cheap "spatial sound" effect (like the "surround" button on low-end hi-fi systems of the time), and on such recordings, computing the average of the left and right channels gives a null output. Some stereo effects (like chorus or reverb) would also make a recording sound less lively or flatter after a mono conversion, but this doesn't really qualify as noise. All these are rare problems, and averaging the L&R channels is the standard way of converting from stereo to mono. In the past I've worked on a system that handled large catalogues of audio files, and my approach was to check whether the energy of the average of the channels was below a certain fraction of the energy of the individual channels ; and if so, used the difference instead of the sum as a mono conversion. Ideally you could compute the cross-correlation between the left and right channels to find the lag at which they are maximally correlated, and delay one channel by the lag before the mixing so they are maximally in-phase with each other, but this is overkill for just handling the 15 or so tracks out of 100,000 that had a massive phase inversion problem - to give you an idea of the rarity of the problem...
The most obvious error is converting from 44kHz to 22kHz by skipping every second sample. This will alias all frequencies in the 11kHz - 22kHz range, and will make the downsampled recording sound "metallic", "crunchy" or "gritty". A proper way of downsampling a recording is to first apply a low-pass filter to remove all frequencies above half the target sample rate ; then decimate (skip every second sample).
I brought in a stereo guitar track to RX 8. The Mixing module allows you to convert to Mono. I select that and Render. It says file created successfully, but when drag it in (or go the Import Audio route), it's still in stereo. Am I missing something? Yes, I know I can convert to Mono in CW, but I'm doing a few other things in RX8 with hiss and hum and would like to take care of all of it in one session. Thanks for any help.
Provides specific control over both left and right signal and balance levels. This simple operation can be used to downmix stereo material into mono, invert waveforms, transcode left/right stereo into mid/side, subtract a center channel, and much more.
I have a mono sample here - extracted from a left channel. I am trying to make that mono signal to stereo. I have a way but somehow i think my way is somewhat - well, complicated is not the right word - but it is not that i am very pleased with how it is achieved.
I was sure i had a mono file as i am sure the source was/is mono only.
What i did not see was that the recording was actually stereo with just the signal on the left channel!
So actually i tried to make a stereo file to sound somewhat stereo.... I know, i know.
Making a mono file seem true stereo isn't a simple matter of EQ or delay. What processes you would use, would depend on what you want to achieve. The Binaural Location plugin is interesting, but it is intended for headphone listening. It might work through speakers but I haven't tried that yet.
For the record, I have 1 of 2 speakers broken, your question came to me the same way for a somewhat different issue/problem. Just converting "stereo to mono" made sense, but so does changing "Balance", so I do each to be double sure.
I have multiple stereo .wav recordings which I want to convert into mono files for further analysis. Is there a way in RavenPro/R/Audacity to batch convert them to mono sound files (channel 1 or channel 2)?
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