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Sound Issue
Im experiencing some sound issues (crackling which is harsh on the ears!) when playing back my projects. The sound issues happen after ive exported the project with the adobe media encoder in premiere 7.0. My audio settings are as follows;
MainConcept Mpeg Audio
Layer II audio
Bitrate: 224
Sample rate: 48khzIt seems to happen SOMETIMES when there is more then one audio track playing (most of the time its fine when both are playing!), ie as well as the video audio (48000hz 16bit stereo), there is background music playing (mp3 44100hz 16bit stereo) at a lower volume. Do i need to be aware of certain good practices when using muliple sound tracks?
I havent played around with the surround sound or anything btw.
Just to clear things up, each seperate sound file is fine and it doesnt harshly distort when i play back the full rendered version within Premiere, so im assuming one of my export audio settings is wrong and is causing this problem after i export?
Thanks in advance for any help!
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3 Replies
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One of the golden rules of Audio is to never – under any circumstances – mix sample rates.
So, before doing anything you should ensure that all sample rates are at 48KHz.
Second rule of Audio is that when you decode a perceptually encoded file – such as one of these ghastly MP3 things – to PCM, and then re-encode to another lossy format, like MPEG audio, you will inevitably get artifacts and often these noises due to recompressing already heavily compressed material.
About all you can do to minimize the effects are to
1 – Not use MP3
2 – If you must use MP3, do not re-export as MPEG audio.
3 – Export at 16/48 LPCM. Then allow the DVD authoring application to create DOlby Digital files, but again be aware that you may still end up with artifacts.
4 – where possible, use uncompressed PCM as your Audio source.Good Audio will never happen from MP3.
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Dammit:E
Great reply, i had a feeling it would be along those lines, ive the cds so will record the songs to pcm!
Thanks very much!
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You may be hearing clipping caused by mixing multiple files that each by themselves is less than 0 db, but combined exceed the limit…that is what the Master Mixer meter is for.
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