[mythtv-users] Advice on getting best archive quality?

Brad DerManouelian myth at dermanouelian.com
Fri Feb 29 22:11:34 UTC 2008

On Feb 29, 2008, at 1:58 PM, Corey Wirun wrote:

> Hi All,
> I'm trying to improve video quality when I archive to DVD.  My  
> recordings are grainy with motion-related artifacts that appear.   
> I'm using the removecommercials scripts that is on the net.   I  
> could use a little advice here on how to get TV quality recordings  
> on disk.
> What I do not understand is the the script (run as a user job) takes  
> a 2.2Gig recording and puts it down to 750K.  Is this where the  
> initial quality loss is?  I understand that the script flags the  
> commercials then transcodes the result to a smaller file.   
> Marginally smaller I can understand due to the loss of commercials,  
> but what is actually reducing the file size by 65%?  Different format?
> Also, is the quality degrading even further because I'm trying to  
> burn 6 hours of programming on a DVD?  If I want near-TV quality,  
> how much recording capacity can I expect on a 4.7Gig DVD?
> I have a PVR-350 and I record using a recording profile with:
> Image size: 720x480
> Video Codec: MPEG-2
> Stream type: MPEG-2 PS
> Aspect: 4:3
> Bitrate: 4500
> Max Bitrate: 6000
You can try bumping this up if you notice compression artifacts in  
your original recordings. I know at this level my blacks looks very  
blocky and it bugs me so I push this a bit higher.

> Audio Codec: MPEG-2 Hardware Encoder
> Sampling: 32000
> Type: Layer II
> Bitrate: 384kbps

You're recording in a DVD-compliant resolution and format so there's  
no need to re-encode anything. You can add cutpoints and use the mpeg2  
-> mpeg2 profile which should just cut and not re-encode the video (in  
a matter of seconds) and then just set up the archive job to not re- 
encode and you will have a DVD at whatever quality your original  
recording is.

I know the mpeg2->mpeg2 encoder has issues at some point, but I think  
it's working now. I'm sure someone will correct me if I'm wrong in any  
of this. :)

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