Pyro Industries API-1394PCI Manual do Utilizador descarregar pdf (Página 68)

■ THE CAPTURE TOOL: CAPTURE CONTROLS

upsample everything to 48 kHz because it is the best sampling rate available. At the

same time, upsampling does little to improve sound quality. It merely puts your audio

in the same envelope as other 48 kHz audio.

Now we need to establish a rule about how Free DV/Xpress Pro will play back

varying sample rates from different media. If you use audio from a variety of tape and

disc formats, it’s a good idea to select Convert Sample Rates When Playing and set it to

Always. This setting will perform a sample rate conversion on the fly when playing

back mismatched samples. Although this solution will work when playing back media,

you will have to convert all of your audio to a single sample rate when outputting your

final edit. If you choose not to convert sample rates while playing, the audio that does

not match the Audio Project sample rate plays back as silence.

If you’re using different sample rates, Free DV and Xpress Pro do not allow you

to output until the rates are all converted to one standard (see Figure 2.22).

Setting Audio Input Levels

If you are using Free DV or Xpress without the Mojo, you can adjust your audio input

levels, as shown in Figure 2.23. Normally, the audio input is set to a unity level. A

unity level is a level that is optimized for best sound reproduction. But you might find

yourself with some media that are recorded with very low audio or, in some cases,

audio that is too hot. Audio that is too loud can be a problem. If the recording was

made with a DV camera, and the audio level goes over the 0 dB level, it will be dis-

torted, no matter what you do. For any digital recording, 0 dB is the point of no

return—the edge of the universe. Whatever you want to call it, 0 dB is the point at

which audio stops being audio and becomes noise. Always avoid this level if possible.

Figure 2.23 Adjusting audio levels

Figure 2.22 Selecting a sample rate

4440c02rev.qxd 11/6/05 9:35 AM Page 47

1 2 ... 63 64 65 66 67 68 69 70 71 72 73 ... 370 371

Sem comentários

Pyro Industries API-1394PCI Manual do Utilizador Página 68