[mythtv] Aspect ratio changes

[Steve Davies]

Timon, John wrote:

> what about just storing the information in the mysql database.  perhaps
> another column.
> 
> just an 'off the top of my head'
> 
> -----Original Message-----
> From: steve at nexusuk.org [mailto:steve at nexusuk.org] 
> Sent: Monday, January 05, 2004 1:32 PM
> To: mythtv-dev at mythtv.org
> Subject: [mythtv] Aspect ratio changes
> 
> 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?

I believe that this information is already encapsulated in MPEG2/4 streams 
(each fram will have a width and height, from which the ratio can be 
calculated?) and this is what the existing scaling code uses to determine the 
output ratios. It seems to work on my DVB-T system, and was working okay when 
I was using a PVR-250.

The problem with using a database is that you would have to record every 
change in the stream (DVB-T streams change ratio at most commertial breaks for 
example)

 >
 > 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).
 >

I think that adding this feature/option to the existing ratio change code 
sounds reasonable.

Just my 2c.

Regards,
Steve

-- 
Steve Davies                   steve at one47.co.uk

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