[mythtv] Aspect ratio changes

steve at nexusuk.org steve at nexusuk.org
Mon Jan 5 13:32:13 EST 2004

My Sky box (and most other decoders) use pin 8 of the SCART connector to 
tell the TV what aspect ratio it should be running in (5v for 16:9 and 12v 
for 4:3).  I would like to include information of aspect ratio changes 
provided by this signal in the stored video, so I would like comments on 
the following idea:

Pin 8 of the input SCART connector would be connected to a serial port on 
the backend via a suitable circuit.

Pin 8 of the output SCART connector would be connected to a serial port on 
the frontend via a suitable circuit (if the frontend and the backend are 
the same machine then this may be the same serial port)

A separate daemon would watch the serial port for changes in the input 
signal and relay them to the backend via a unix domain socket.  Similarly 
the frontend would be able to send aspect ratio changes to the daemon via 
the unix domain socket.

Now, the bit I'm not sure about is how to incorporate the data into the 
video stream - I'm thinking of doing the same as the 
NuppelVideoRecorder::WriteText() function but use a different frametype.  
Would this seem to be the best way to handle the data?

There would be a user configurable option to tell the frontend whether to 
send signals to the daemon when it wants to change the aspect ratio or to 
use the existing aspect ratio changing code (which scales the video).


 - Steve                                             http://www.nexusuk.org/

     Servatis a periculum, servatis a maleficum - Whisper, Evanescence

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