Horizontal Scaling Using TMS320DM648 Evaluation Board

Gabriel Quintana

Other Parts Discussed in Thread: TVP5154

Hello There:

I was wondering if there is a way to scale video horizontally to QCIF.

I know that you can scale down from 4CIF to CIF using the scale parameter in VPORTCAP_Params, however I can't see a way to go to QCIF (Without doing a manual scaling).

I found a way of scaling down video by manipuling some registers on the TVP5154 video decoder, however the problem that I found is that the chroma buffers are reversed (Cb becomes Cr and Cr becomes Cb) and my concern is that this issue can be intermittent instead of permanent since I have no idea what is causing the problem.

Any help would be appreciated.

Thanks;

Gabriel

over 17 years ago

0 TimHarron over 16 years ago

TI__Mastermind 18130 points

The VPort cannot handle this scaling, but I believe the TVP5154 should be capable of doing this. I am not sure why you are seeing buffer reversal, but I am checking with the factory folks to see if they can comment.

0 Gabriel Quintana over 16 years ago in reply to TimHarron

Intellectual 430 points

Thanks Tim for your response.

Is this issue has to do with the fact that the TVP5154 uses the AVID signal to do the scalling and the DSP does not use it (Because is fisically disconnected)?

0 TimHarron over 16 years ago in reply to Gabriel Quintana

TI__Mastermind 18130 points

Gabriel,

I believe that the AVID signals are used to crop out a smaller portion of a larger active frame but are not actually used for scaling purposes. AVID uses registers 11h-14h while there are actually vertical and horizontal scaling registers at 3A8h-3ADh.

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Horizontal Scaling Using TMS320DM648 Evaluation Board