[mitch]

Here is a correspondence between myself and Womble Multimedia Technical Support, in case others might have similar questions. The current release of these tools is 12/22/2004: (with replies)

Quote:

Hello,

I recently purchased your MPEG Video Wizard product (3/19/05) and have the following questions regarding functionality. Some questions may apply to MPEG-VCR as well.

1. MPEG GOP Fixer, Video and Audio PTS
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The MVW help manual states, "Video and audio Presentation Time Stamps are 33-bit integers inserted in an MPEG stream to allow an MPEG decoder to synchronize the decoded audio sound with the decoded video image display. Those PTS values should match the playback time length of the decoded audio sound with the video frame rate. When they are in error, the MPEG movie cannot be played correctly, and the audio and the video will be out of sync. The GOP fixer tool will correct those PTS errors based on its calculation from the complete audio data. It will only modify the erroneous 33-bit integers."

Question: Assuming you have a few missing video frames in a file and no missing audio frames (or vice versa). Would the GOP Fixer just renumber the referenced frames so they will be in sequence again, or would the GOP Fixer also throw out associated audio frames where the video frames are missing (as well as renumber the frames) in order to keep the whole file in perfect synchronization?

Yes, just renumber the PTS time stamps. No data will be deleted or added, except the modification of the bits corresponding to the PTS time stamps.

2. Audio Editing (using the sound line)
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When using the sound line editor and only changing a small amount of audio (with respect to the overall length of an A/V clip), the "Details" button on the Export screen implies that the audio in the whole clip is re-encoded (audio line for the whole clip is displayed red instead of only the actual (small) part that was edited). Can you confirm if the audio in the whole clip is re-encoded instead of only the part that was changed?

The audio for the whole clip will be re-encoded. This is to avoid the problem of a possible audible discontinuity near the crossing point, if only the modified part is re-encoded.

3. Options (observations)
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There appear to be some items included in the Options screens that are not listed in the help manual.

Yes. The help manual needs to be updated.

> Examples:
> Preview/Hardware Video Overlay Acceleration
> AVSync (whole list)
> KeyMap (whole list)
> Export/MPEG-1 audio encoder

Thanks for pointing out the list of items.

4. Log Reports
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Are there plans to add log reports (that may be saved in text files, for example) for items such as those in the Tools area (GOP Fixer, for example)?

No. But I have added your suggestion to the list of features to be considered for a future update.