   |
Audio Considerations for VideoClipstream
Audio Settings:
When creating a VideoClipstream
movie, the audio settings must be selected with the video quality in mind.
If the decision is to select better quality audio, the quality of the
video will need to be adjusted accordingly. In general, the audio settings
in the pre-set settings files (and in the table below) are appropriate
for the related speeds.
- Enhanced Rate Conversion; Be sure to always select 'Best' from the pull down window. Otherwise, the result will be poor audio quality with a lot of ringing, hiss, etc. Also note: there is a bug in Premiere whereas it will not use the new setting after a movie has already been exported without Best selected. Premiere must be restarted and the setting changed to 'Best' if something such as 'Good' was previously selected. View a Screenshot.
- After configuring advanced audio settings (click to view), Premiere 5.x will crash during the next usage due to a bug in the software unless the preference file prem50.prf is deleted before restarting. Remove the Preference file Prem50.prf (click to view) before launching Premiere again to resolve the problem and avoid a crash. Default path: C:\program files\adobe\Prem50.prf}. This problem has been resolved in Premiere 6.0. We strongly recommmend that users of Premiere 5.xx upgrade to Premiere 6.0.
- Connection Speed minus audio data rate divided by 8 equals data rate. Therefore, data rates should coincide with each other (example: for a 56k sample, if the audio data rate has been set at 16, the data rate should be set to 4)
- Here are some general guidelines for Audio settings at various speeds:
| Connection speed |
28k
|
56k
|
100k
|
150k
|
200k
|
300k
|
500k
|
|
Data
rate
|
2
or 1
|
4
or 5
|
10
|
16
|
22
|
37
or 32
|
58
|
|
Audio
Data rate
|
8
or 12
|
16
or 8
|
20
|
20
|
20
|
20
or 24
|
32
|
|
Optimization
|
music
|
music
|
music
|
music
|
music
|
music
|
voice
|
|
Emphasis
|
86
|
86
|
86
|
86
|
86
|
86
|
86
|
Audio
Exporting in Premiere:
The following is a step by step process for extracting/down sampling
the audio with Premiere in preparation for VideoClipstream™.
Although not always essential, audio quality results may be better after
down sampling. This process can also be performed with another audio program
such as Syntrillium's Cool Edit.
As with all VideoClipstream™ encoding, take note of the source file properties. (right click on the opened movie in Premiere and select 'Get Properties') Upon seeing 'Compressor = QDesign Music 2', down sampling must be performed if you're using Premiere 5.xx. Take note of the sampling rate. (example: 44kHz, 16 bit stereo) Also, because of a bug in Premiere, if the Sampling rate is 48kHz down sampling prior to encoding is necessary.
- Go to File>Export>Audio,
click on the Settings tab.
- Under General Settings, Select from the pull down menu, File Type: Windows Wave Form.
- 'Open When Finished'
is a default setting and will be useful in this case. The Range should
be 'Entire Clip'.
- Go to Audio
Settings. Rate and Format should coincide with those
listed in the source file Properties. (example: 44kHz, 16 bit stereo)
- Click 'OK' and Save to a desired location.
- File>Open
the new wav file if 'Open When Finished' was not enabled.
- Go to File>Export>Audio and click the Settings tab.
- Go to Audio Settings
and select 8kHz 16bit Mono
- Click 'Okay' and save the new wav file with a new name.
- File>Open
the down sampled file. If the source movie isn't still opened, open
it as well.
- Go to File>New->Project.
Click okay in the dialogue box. Go to Window/Timeline.
- Drag the video
into the timeline (Video 1A). Select Audio 1 and delete it from the
project. Drag the new, downsampled audio into its place (Audio 1)
- Ensure the Timeline is selected, Go to File>Export/Movie and carry on as per usual for VideoClipstream™ encoding.