I'm primarily recording audio for clients and checking it against their choreography video for timing. I have to have the best audio to send to them. If I export the audio as 48 and resample in audio software to 44.1, am I damaging the audio?

@beth-hall

. . . . . I have to have the best audio to send to them. . . . .

Audio has several parameters which affect the quality of the audio, the 2 main ones which affect quality are Sample rate which has been explained by Jeff above and Bitrate

Of these 2 parameters it is the Bitrate that has a larger effect on quality - set this too low and the effect is noticeable eg loss of higher frequencies, a more muddy sound.

For CD quality the Sample rate is 44.1kHz and the Bitrate about 160 kbps.

For higher quality the audio bitrate should be set to 256 kbps or 320kbps (maximum).

With respect to the Sample rate and Jeff's comment 'removing any frequencies between about 22.05kHz and 24kHz, which are basically inaudible to human ears anyway'.

I agree that they are inaudible, however for many audio aficionados (I am an ex hifi buff) or someone who has a very good musical ear, there is a loss of timbre in instruments which have a wide range of strong harmonics eg cymbals.

Note: if you are burning audio CD's to send to your clients then all the above is irrelevant - the audio will be converted to CD quality ie 160 kbps 44.1kHz audio as required by the relevant CD disc standards.

HTH

John EB

Once a client approves their music, I burn the audio file to CD for use in competition. In order to approve music, I send a video with music synced to choreography. If a video has enough quality, I sometimes put on my website or at YouTube as a sample of my music editing work. I'm finding it extremely useful to have the object stretch mode in video to make final tweaks to timing, so I want this audio to be the basis of my final music file. As I understand it from answers above, I can convert from 48 in the video file back to 44.1 in my samplitude audio software with no perceptible loss of audio quality. Is that correct?

Hi

. . . . I can convert from 48 in the video file back to 44.1 in my samplitude audio software with no perceptible loss of audio quality. Is that correct? . . . .

Considering the typical devices that are going to play the video from a website there would be no perceptible difference in audio quality, however I am puzzled why you would want to add an additional step to the video process when it is not necessary the required changes can be made in MEP depending on:

1. the sample rate of the original audio recording
    
2. the bitrate of the original audio

If the original recording is 44.1 kHz then set the MEP project audio rate to 44.1kHz in the project settings

If the original recording is 48kHz then leave the project setting at 48kHz and change the export audio bitrate to 44.1 kHz eg for mp4

Click the Advanced button (1), then change the audio bitrate (2) and if you want to save this as a preset for future use click the disc icon (3) and give the preset a name, this will then appear in the preset drop down list.

There is no need to increase the audio bitrate - this can remain at 160 kbps.

Note your project settings and export advanced dialog may be different to mine depending on the version of MEP you have and the codecs used for encoding the video.

HTH

John EB

There are stern warnings in the help manual about changing the sample rate to 44.1 in video software (the music may not play after I render). It would be far preferable to me to leave the sample rate at 44.1 throughout the project as I bounce between audio and video. If it's safe to use 44.1 in video, I'll do that. Thank you for all the information.

I'm curious to know about the "stern warning" on the Help manual. I only see a warning about exporting to MPEG-2 format.

Here is what the VPX manual says about what to do when starting a project:

"Audio sample rate: The preset sample rate is 48 kHz. This sample rate is used for all recordings and is also the standard setting for DVD audio tracks. This setting guarantees optimal sound quality. Audio material at different sample rates (e.g. CD audio with 44 kHz) is automatically converted when loaded (resampling). Only change this value if you want to use audio with a different sample rate or if your sound card does not support this sample rate.
Note: The audio sample rate can only be changed in empty projects. When an object is added to the project, this setting is locked."

This is for exporting to MPEG-2 format:

"Sample rate  (Hz): Here you can set the sample rate for audio encoding. For DVDs the standard is set to 48 kHz. If you change the settings here, it may result in not being able to play back the sound or the entire video."

And this is for exporting to MPEG-4 format:

"AAC audio can be encoded with a sample rate of 8000, 16000, 24000, 32000 or 48000 Hz in either mono or stereo. By default, the sound is set to 48000 Hz stereo. The higher the sample rate is, the larger the resulting file and higher the audio quality. You can use the technical specifications of your playback device to help with this."

The manual for Magix Audio & Music Lab mentions:

"Sample rate: This sets the sample rate of the project. For maximum sound quality, the sample rate of the project should agree with the sample rate of the recorded or imported material. 44 kHz is preset. If you are planning to edit video sound, you should change the sample rate before importing video files (whose audio track is mostly available with 48 kHz)."

Like John EB, leave the setting in the video program the same as the recorded frequency.

I recall reading in the Samplitude forum that it is okay to go from 48 to 44.1 kHz, but not the other way. As Jeff mentioned, you lose some if you do this. But, if you start with 44.1 and want to go to 48, I don't think that you can get the frequencies that are missing. Thus, always go down, never up. Guys, is this correct?

John CB