[mythtv-users] real format of .nuv from DVB-T card (mpeg2 with no header?)

Ian Ward support at cyberpro.com.au
Mon Aug 15 10:00:48 UTC 2005

ffrr wrote:

>I have often read that the content of the .nuv files that mythtv records 
>from my DVB-T card, is already an mpeg2 file.  However, DVDstyler (which 
>I am using to make the DVD iso image) does not accept the file, if I 
>just rename it to .mpg.  I get the following errors...
Hey there.  my setup - Mythtv 18.1 with DVB-T cards in Sydney.
I recorded some shows for a friend, then said I would put the shows on DVD.
Boy, do I regret that.
I cannot believe how @#$ hard this is ( especially using bloody Windows )

Everything I tried to use wanted to re-convert and re-convert AND 
RECONVERT the file.

Anyway, here goes.
Please anyone feel free to correct me, this just represents my hard won 
"rationalisations" based on what I see and how I get things to work  ( 
often not understanding why )

In the early days of my system, I would lose sound when switching 
between certain channels.  Also , in the occasional recording the sound 
would drop out completely ( for the rest of the recording ).  A google 
search provided the answer, back in your mythtvsetup -> capture Cards -> 
dvb:0 -> advanced -> recording options , select "record in ts instead of 
ps format" for each card.

So now I know my "nuv" files are raw as they come off "the wire" and why 
when recording two channels at once the box only shows 2% CPU useage ( 
suck eggs non DVB people !! ).

Yes, DVB-T is MPEG2 , but the "stream" is in a slightly different 
format.  Think of it like a divx.avi file.  The avi is a container with 
MPEG4 Video and MP3 Sound woven together.  TS is the multiplexed stream, 
Video and Sound and Subtitles and Teletext( I presume)

I also have dvb-t card in my windows box so I have the codecs supplied 
by dvico installed so I hope your experience will be the same.

at attempt #453
either use nuvexport to go mpeg2->mpeg2 or simply go grab the 
ringbuffer.nuv or recording.nuv file.
go and get:
This will read a ts ( digital transport file ) in Windows, you can edit 
out the commercials, and write a correct mpeg2 file that winamp or 
anything will play.  It's fast, it's good, it's a breeze, it's FREE.

the mpeg file(s) are pretty big though as our SD is still 720x576.
you can use any dvd authoring tool to create a dvd.  But it's still a 
HUGE PITA.  Your PC will be busy for HOURS.
you will end up with a standards compliant DVD though.

I take it you have successfully installed nuvexport.
nuvexport is great, you browse your shows using the database names and 
they are exported in many formats.
It also shows you what format the nuv files are.  My early ones from 
June/July are RJPG but later ones after the change to raw TS are 
reported as MPEG2 16:9

At the end of the day, I thought it was crazy to kill my windows PC for 
hours when Linux can do this standing on it's head ( after the 
obligitary frigging around in the dark for a few hours )

So at attempt # 647 ,
There is a section on the mythtv FAQ about copying to DVD. 
So, I installed dvdauthor ( install with apt ), and followed this  

Run nuvexport ( I chose half resolution, low priority )
#nuvexport --mode dvd --height 288 --width 360 --nice 19

I also choose audio bitrate to 128 ( from 384 ), video bit rate 2000 
instead of 6000, no cropping or de-interlacing.
running at nice 19 means we just use spare cpu cycles.  On the AMD 
1.8Ghz it takes 11 minutes per 15 minutes of TV ( even with the family 
watching TV )  15 Minutes ( one episode of Very Little Britain ) makes a 
200 Megabyte mp2 file.
( it complains about not knowing the aspect ratio but still works, I 
guess I'll look into this next time someone wants me to create a DVD for 
them, just another switch on nuvexport I expect )

you could just drag that mp2 file into windows, or use dvdauthor like 
# dvdauthor -o subdirectoryname -f  file1.mpg file2.mpg file3.mpg ........
# dvdauthor -o subdirectoryname -T

That creates a subdirectory with AUDIO_TS and VIDEO_TS with all the IFO 
files you need for a DVD structure.

You can drag into your favourite burning software in winblows. ( like 
nero ) or use any one of the linux burners like:
#|growisofs -Z /dev/scd0 -dvd-video subdirectoryname|

Hope this helps.

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