Is there a 'standard' mixing set of values for converting 5.1 surround into
stereo?

I've started doing some experimental recordings of 'HDTV' and recorded last
night's broadcast of the 'broadway' prom on BBC HD. This has 5.1 surround.
I can extract this as '6 channel LPCM', but then am not sure what balance
of mixdown the BBC and commercial TV set makers, etc, assume you'd apply to
convert to stereo.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

On Sun, 02 Sep 2012 16:49:57 +0100, Jim Lesurf
wrote:

Is there a 'standard' mixing set of values for converting 5.1 surround into
stereo?

I've started doing some experimental recordings of 'HDTV' and recorded last
night's broadcast of the 'broadway' prom on BBC HD. This has 5.1 surround.
I can extract this as '6 channel LPCM', but then am not sure what balance
of mixdown the BBC and commercial TV set makers, etc, assume you'd apply to
convert to stereo.

Slainte,

Jim

Jim,

Does this have what you need?

http://broadcastengineering.com/mag/...surround_sound

d

On Sun, 02 Sep 2012 16:49:57 +0100, Jim Lesurf
wrote:

Is there a 'standard' mixing set of values for converting 5.1 surround into
stereo?

I've started doing some experimental recordings of 'HDTV' and recorded last
night's broadcast of the 'broadway' prom on BBC HD. This has 5.1 surround.
I can extract this as '6 channel LPCM', but then am not sure what balance
of mixdown the BBC and commercial TV set makers, etc, assume you'd apply to
convert to stereo.

Slainte,

Jim

OK, it is here.

http://jaadec.sourceforge.net/specs/...-4_General.pdf

Para 4.5.1.2.2 is the part you need.

d

In article , Don Pearce
wrote:
On Sun, 02 Sep 2012 16:49:57 +0100, Jim Lesurf
wrote:

Is there a 'standard' mixing set of values for converting 5.1 surround
into stereo?

I've started doing some experimental recordings of 'HDTV' and recorded
last night's broadcast of the 'broadway' prom on BBC HD. This has 5.1
surround. I can extract this as '6 channel LPCM', but then am not sure
what balance of mixdown the BBC and commercial TV set makers, etc,
assume you'd apply to convert to stereo.


http://jaadec.sourceforge.net/specs/...-4_General.pdf

Para 4.5.1.2.2 is the part you need.

Excellent! Thanks, Don, for both references. :-)

Having done my first experiment with recording HDTV from DVB-T2 I'm wanting
to compare the audio with the SD version. However the snags a

A) SD uses stereo, but HDTV can (and does) use 5.1.

B) The HD recordings often switch audio format during a stream.

The first means I need a 'standard' for the 5.1 to stereo mixdown. So the
references you gave are ideal as they are clear and obviously 'standards'.

The second is a PITA because most software (inc VLC and ffmpeg) get
confused when the format changes midway though a file recorded from a
broadcast transport stream. (Same with ffplay and parole.) It seems that
authors have made the assumption that the format at the start will be
maintained throughout. Reasonable for most files... But not so for HDTV!

I'm going to see if I can write something that helps 'automate' the process
of locating 'boundaries' in a recorded transport stream (.ts) file, then
process down any 5.1 into stereo. I can use ffmpeg (or VLC) for
conversions, but need to find the boundaries, and then apply a standard
conversion.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

"Jim Lesurf" wrote in message ...

In article , Don Pearce
wrote:
On Sun, 02 Sep 2012 16:49:57 +0100, Jim Lesurf
wrote:

Is there a 'standard' mixing set of values for converting 5.1 surround
into stereo?

I've started doing some experimental recordings of 'HDTV' and recorded
last night's broadcast of the 'broadway' prom on BBC HD. This has 5.1
surround. I can extract this as '6 channel LPCM', but then am not sure
what balance of mixdown the BBC and commercial TV set makers, etc,
assume you'd apply to convert to stereo.


http://jaadec.sourceforge.net/specs/...-4_General.pdf

Para 4.5.1.2.2 is the part you need.

Excellent! Thanks, Don, for both references. :-)

Having done my first experiment with recording HDTV from DVB-T2 I'm wanting
to compare the audio with the SD version. However the snags a

A) SD uses stereo, but HDTV can (and does) use 5.1.

B) The HD recordings often switch audio format during a stream.

The first means I need a 'standard' for the 5.1 to stereo mixdown. So the
references you gave are ideal as they are clear and obviously 'standards'.

The second is a PITA because most software (inc VLC and ffmpeg) get
confused when the format changes midway though a file recorded from a
broadcast transport stream. (Same with ffplay and parole.) It seems that
authors have made the assumption that the format at the start will be
maintained throughout. Reasonable for most files... But not so for HDTV!

I'm going to see if I can write something that helps 'automate' the process
of locating 'boundaries' in a recorded transport stream (.ts) file, then
process down any 5.1 into stereo. I can use ffmpeg (or VLC) for
conversions, but need to find the boundaries, and then apply a standard
conversion.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Phew, that is so convoluted and time consuming!
With a PCI card installed in a Win7 machine it is so simple, we just open
the
supplied software and configure for 2 channel PCM.
With a set top box all have similar menu's, and again it is so simple we
just
open the menu and select 2 channel PCM output. An example in following clip
at 1 min and 7 sec:
NOS DAC TDA1541
http://www.youtube.com/watch?v=9GDeKbkvTiQ

NOTE: No copyright infringed on any of my current clips.
Above clip contains some brief guitar picking tracks from approx 12 years
back.

In article , FedUpLurker

It would help if you were able to put your text into the *body* of your
posting, not below my sig. But maybe your 'Windows' experience doesn't go
that far... :-)

However I've rescued what you wrote from below the sig sep.


]
] Phew, that is so convoluted and time consuming! With a PCI card
] installed in a Win7 machine it is so simple, we just open the supplied
] software and configure for 2 channel PCM. With a set top box all have
] similar menu's, and again it is so simple we just open the menu and
] select 2 channel PCM output.

Yes, that is easy to do with a lot of software if all you want to do is
watch and listen.

However I'm interested in doing an analysis of the actual audio data as
well as checking what consumer-grade software and hardware does to the
data. This includes assessment against standards, etc, rather than
what one company decides to do.

I'm also interested in the details of what is in the transport
packeting broadcast. FWIW I've already found one or two odd sections where
broadcasts from TXs aren't consistent. I find this interesting as it may
explain occasions where people with some kit receiving one TX get a problem
whilst others say that they do not.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html