Freeview radio bitrate
 

I heard that DTT bitrates are better than DAB. However, when I flicked
through 'The Hits Radio' on my TV it sounded like it was coming from a
cardboard box.

What bitrate are they using?

And I assume they are using MP2 encoding. How does this compare to MP3?
E.g., if you assume that a 192kps mp3 is minimum bandwidth for radio
(if you were buying them you would want something better, but that's
good enough for radio broadcast), what would the equivalent MP2 bitrate
be?

wrote in message
ups.com...
I heard that DTT bitrates are better than DAB. However, when I flicked
through 'The Hits Radio' on my TV it sounded like it was coming from a
cardboard box.

What bitrate are they using?

And I assume they are using MP2 encoding. How does this compare to MP3?
E.g., if you assume that a 192kps mp3 is minimum bandwidth for radio
(if you were buying them you would want something better, but that's
good enough for radio broadcast), what would the equivalent MP2 bitrate
be?


192kbs is minimum for radio. Most of it is way below that.

Regards

wrote in message
ups.com...
I heard that DTT bitrates are better than DAB. However, when I flicked
through 'The Hits Radio' on my TV it sounded like it was coming from a
cardboard box.

What bitrate are they using?

And I assume they are using MP2 encoding. How does this compare to MP3?
E.g., if you assume that a 192kps mp3 is minimum bandwidth for radio
(if you were buying them you would want something better, but that's
good enough for radio broadcast), what would the equivalent MP2 bitrate
be?

Double that. 384 Kbps.

I heard that DTT bitrates are better than DAB. However, when I flicked
through 'The Hits Radio' on my TV it sounded like it was coming from a
cardboard box.

What bitrate are they using?

ISTR reading that some of the multi-platform radio stations have pretty
grotty links between platforms. So even if it has sufficient space on
Freeview, they may be spoiling the ship for a ha'porth of bandwidth
elsewhere. Even so, with Freeview capacity limited and EMAP having a RUCK of
stations.. I suspect they're guilty of staking 'em high and pricing them
cheap like the DAB operators (of which they are one, of course)

On Tue, 11 Oct 2005 14:03:43 +0100, "Terry"
wrote:


wrote in message
oups.com...
I heard that DTT bitrates are better than DAB. However, when I flicked
through 'The Hits Radio' on my TV it sounded like it was coming from a
cardboard box.

What bitrate are they using?

And I assume they are using MP2 encoding. How does this compare to MP3?
E.g., if you assume that a 192kps mp3 is minimum bandwidth for radio
(if you were buying them you would want something better, but that's
good enough for radio broadcast), what would the equivalent MP2 bitrate
be?


192kbs is minimum for radio. Most of it is way below that.

How can it be the minimum then? Do you mean the maximum?

Scott

wrote:
I heard that DTT bitrates are better than DAB. However, when I flicked
through 'The Hits Radio' on my TV it sounded like it was coming from a
cardboard box.

What bitrate are they using?

There's a full list of bitrates at the bottom of this page:

http://www.digitalradiotech.co.uk
(takes a while to load)

The BBC use higher bitrates on DTT than DAB. In most cases this gives
higher sound quality, though on Radio 3, where the bitrate is sometimes
equal on both platforms, there's a slight issue with the DTT feed which
make DAB higher quality in this one instance only.

Most of the commercial stations on DTT use 128kbps, which is too low
for high quality stereo music. However, the 128kbps stations on DTT
sound very bad, and I think the feed into the final 128kbps encoder
must already sound poor, probably coming from at least one previous
generation of 128kbps encoding, if not several. You can't cascade audio
encoding like this without dire consequences, just like you can't dub
from VHS to VHS to VHS without wrecking the picture quality.

And I assume they are using MP2 encoding. How does this compare to MP3?
E.g., if you assume that a 192kps mp3 is minimum bandwidth for radio
(if you were buying them you would want something better, but that's
good enough for radio broadcast), what would the equivalent MP2 bitrate
be?

The type of artefacts produced by the two encoders would be different,
but the equivalent bitrate is about 224-256kbps.

The full answer is that it depends on the encoder, and what you're
encoding. It would be easy to find a combination of encoders+test clip
where mp3 sounded worse at 256kbps than mp2 sounded at 192kbps, but
overall you'd expect the advantage to be the other way around, with the
advantage decreasing as the bitrate increases.

No bitrate is _always_ transparent (i.e. perfect) for either encoder,
however well encoded 192kbps isn't transparent for mp3 for significant
amounts of critical material and listeners. Well encoded 256kbps mp2
isn't either, but to my ears its preferable on the content I'm more
likely to listen to. It would be a good choice for digital radio
(though a modern codec like AAC would be a much more efficient and
slightly higher quality choice).

Cheers,
David.