[BC] DTV Audio Levels

[towers at mre.com]

Not always the case Richard.  Recall this same problem ocured when video
passed through a number of frame syncronizers, but the audio went a
different route.  Put enough syncronizers in line and the audio could
easily get seperated.  Particulalrly on live interviews at sports events
which go through networks.

That was remedied somewhat when the cameras started to include the audio
with the video via triax and the one audio source delayed in the CCU
withthe video.

But I have seen/heard TERRIBLE out of sync conditions pre-DTV conversion.
Many times of PBS where they couldn't afford audio delay syncronizers on
everything

MM

> I don't think it would take more than a few milliseconds to process the
> audio. There shouldn't be an resynchronization problems because
> synchronized audio was delivered with the video. Synchronization problems
> come into play when one has multiple paths for both the video and the
> audio. The TV station already has synchronized audio available from the
> network. Extracting digital audio from the composite signal is a trivial
> operation, with the maximum latency determined by the dictionary length in
> the compression. This is all "realtime" as far as audio is concerned,
> consuming a few tens of audio frequency cycles, maximum. Actual signal
> processing is instantaneous when related to slow varying information like
> audio.
>
> Cheers,
> Richard B. Johnson
> Book: http://www.AbominableFirebug.com/