How Does SageTV Recording Quality Translate to MPEG2 Encoder Options?

[rdellar17]

Does anyone know how the settings under SageTV "Recording Quality" translate to the actual encoder options sent to the MPEG2 encoder card? (i.e. Average, Min, Max bitrates and CBR/VRB options.) And if there is any way to tweak those options?

I specifically have a Hauppauge 2250 (WinTV-7164) capture card. But I figure there is a standard way that SageTV is passing parameters to the family of cards.

I can see the transcoder options in the Sage.properties file (transcoder/formats/DVD) that show bitrates, but those don't correlate to the Recording Quality options.

I was playing around with WinTV that comes with the card and this is how they pass the values to the card:
(They have a fair, good, better, best and list the bitrates for each. Somewhat similar to SageTV...)
http://ftp.hauppauge.co.uk/board/sho...d.php?p=100228

I also found how you can set the audio gain on the card, but this is extremely model specific:
http://hauppauge.co.uk/board/showthread.php?t=17156

(I figured this was a bit more of a software question than hardware.)

[nyplayer]

Maybe this will help

http://www.sagetv.com/2_papers/HPquality.txt

[rdellar17]

Originally Posted by nyplayer

Maybe this will help

http://www.sagetv.com/2_papers/HPquality.txt

Thanks, now that I know the property to search for "python2_encoding", I found a few interesting posts on this...

From the FAQ (how to create your own. And p277 of the manual, section H.)
http://forums.sagetv.com/forums/show...2960#post42960

and a related thread with newer posts from 2010: (I assume these are passed to the encoder from the discussion. Opus4 said that "The default qualities are no longer written to the properties file." in the second post... If they were I'd have my answer... Worst case I could just create my own and then I'd know what there were.)
http://forums.sagetv.com/forums/showthread.php?t=33407



I couldn't find anything about what the default SageTV settings correspond to though. It would be especially nice to know which are CBR and which are VBR... I guess I could open an official support ticket, they could probably tell me exactly what the settings since they are probably just the exact same python2_encoding strings, but not exposed it the properties files.

[Tiki]

Of course you know that the HVR-2250 supports both analog and digital. The encoding options you are referring to only apply to analog recordings.

If you are recording clear-QAM from cable or ATSC over the air digital, this card just grabs the digital stream in whatever format it was transmitted. It does not transcode digital signals to some other format, so the quality settings have no effect.

If you are recording analog cable or getting the output of a set top box via composite or S-Video, then you are talking analog and the settings you mention will apply.

[stanger89]

Originally Posted by rdellar17

Thanks, now that I know the property to search for "python2_encoding", I found a few interesting posts on this...

From the FAQ (how to create your own. And p277 of the manual, section H.)
http://forums.sagetv.com/forums/show...2960#post42960

and a related thread with newer posts from 2010: (I assume these are passed to the encoder from the discussion. Opus4 said that "The default qualities are no longer written to the properties file." in the second post... If they were I'd have my answer... Worst case I could just create my own and then I'd know what there were.)
http://forums.sagetv.com/forums/showthread.php?t=33407



I couldn't find anything about what the default SageTV settings correspond to though. It would be especially nice to know which are CBR and which are VBR... I guess I could open an official support ticket, they could probably tell me exactly what the settings since they are probably just the exact same python2_encoding strings, but not exposed it the properties files.

Those listed in the FAQ are the defaults I believe.

[rdellar17]

Originally Posted by Tiki

Of course you know that the HVR-2250 supports both analog and digital. The encoding options you are referring to only apply to analog recordings.

If you are recording clear-QAM from cable or ATSC over the air digital, this card just grabs the digital stream in whatever format it was transmitted. It does not transcode digital signals to some other format, so the quality settings have no effect.

If you are recording analog cable or getting the output of a set top box via composite or S-Video, then you are talking analog and the settings you mention will apply.

Yup this is for capturing S-Video...

[rdellar17]

Originally Posted by stanger89

Those listed in the FAQ are the defaults I believe.

Cool. Well that works out well then for me.

[rdellar17]

I wanted to update this thread since the information listed in it is incorrect.

Basically the settings listed in the FAQ do NOT correspond to how the analog recordings are setup.

HERE is a thread from 2005 that shows how they really work. (From the 3-4 I tested these appear to be correct.)

Here is the text version of the table in the PDF.

Quality		VBR	AvgVideoRate	Resolution	AudioBitrate
Best		No	6Mbps		720x480		384kbps
Great		No	3.8Mbps		720x480		384kbps
Good		No	2.8Mbps		480x480		256kbps
Fair		No	1.7Mbps		480x480		256kbps
CVD		Yes	2.5Mbps		352x480		224kbps
SVCD_ELP	Yes	1.152Mbps	480x480		224kbps
SVCD_LP		Yes	1.6Mbps		480x480		224kbps
SVCD_SP		Yes	2Mbps		480x480		224kbps
DVD_ELP		Yes	3Mbps		720x480		384kbps
DVD_LP		Yes	4.8Mbps		720x480		384kbps
DVD_SP		Yes	6.4Mbps		720x480		384kbps
MPEG2Max	No	12Mbps		720x480		384kbps

Below is a follow up thread on this one... Still trying to find the best way to encode with SageTV.
http://forums.sagetv.com/forums/showthread.php?t=55546