[mythtv-users] Question on recording sizes and DVD burning

[John Pilkington]

On 21/01/14 14:27, Joseph DeGraw wrote:
> On 01/21/2014 09:08 AM, Joseph DeGraw wrote:
>> A while ago I upgraded my hardware to include HD recording with a ceton
>> card and its been great. However, My girlfriend wants to burn some of
>> her shows to DVD that are 2 hours long. However the size of the files
>> are like 10 gigs. In mytharchive they can come down to just over 5 gigs.
>> The shows are 1920x? HD from comcast provider. I was thinking that
>> reducing them to 720i would be fine to make them smaller to fit on DVD.
>> This brings up transcoding (which Im looking into right now) and profiles.
>>
>> How do you handle this?
>>
>> jdegraw

>>
> Ok, I have gone into the menu in mytharchive after reading an older
> thread and selected a recording profile. I guess my only question is :
> What do the different profiles mean?
>
> HQ, EP, LP, SD
>
> I know if I select a SD setting it will not finish and stalls out. I
> dont even get an error message. Therefore, Iam trying the LP one for a
> single sided DVD for a 10 gig, 2 hour Lifetime Network movie.
>
> MythTV .27 / Mythbuntu 12.04 based
>

With much of the USA now apparently HD only this is clearly getting to 
be a common problem, and at present I don't think MythArchive handles it 
well.  The encoder options are defined here: (Fedora build)

/usr/share/mythtv/mytharchive/encoder_profiles/ffmpeg_dvd_ntsc.xml

and are used within /usr/share/mythtv/mytharchive/scripts/mythburn.py

I suspect that the best option would be two-pass specifying the required 
file size; a fairly minor edit of the HQ option, probably, but requiring 
some research in the ffmpeg documentation or code.

As far as I can see the -b:v value doesn't do much.  The pal-dvd 
profile, which I use, seems to focus on a q value of 2 as its guiding 
light.  That isn't specified in the file above.

If at present you are getting a 5 GB file the m2vrequantiser option 
within MythArchive will shrink that quickly with a quality that should 
be acceptable, but I wouldn't like to rely on it for much higher ratios.

HTH

John P