[mythtv-users] recording radio as mp3 instead of mpg?

[Brad Fuller]

On Tue, Jul 22, 2008 at 6:09 PM, Nick Rout <nick.rout at gmail.com> wrote:
> On Wed, Jul 23, 2008 at 11:41 AM, Brad Fuller <bradallenfuller at gmail.com> wrote:
>> On Tue, Jul 22, 2008 at 4:35 PM, Nick Rout <nick.rout at gmail.com> wrote:
>>> On Wed, Jul 23, 2008 at 8:50 AM, James Stembridge <jstembridge at gmail.com> wrote:
>>>> On Tue, Jul 22, 2008 at 6:59 PM, Udo van den Heuvel <udovdh at xs4all.nl> wrote:
>>>>> Can I configure MythTV somehow to record radio as mp3 file, instead of
>>>>> mp3 inside an mpeg stream?
>>>>> (I know I can dump the audio from the mpeg but I would like to skip that
>>>>> step)
>>>>
>>>> I assume you're talking about radio channels on dvb-t?
>>>>
>>>> If so the audio is probably mp2 rather than mp3, at least that's
>>>> certainly the case here in the UK. Assuming this is the case for you
>>>> too you'll obviously have to transcode, there's a contrib script that
>>>> does that.
>>>
>>> One thing I am curious about, how different is an mp2 stream from an
>>> mp3 stream? Is it backwards compatible? Can I change the file
>>> extension from .mp2 to .mp3 and fool my ipod? If so you really only
>>> need to demux the stream and change the extension.
>>
>> no. MP3, is actually a nickname for MPEG-1 Audio Layer 3.
>>
>
> Whats your point? mp2 is a nickname for MPEG-1 Audio Layer 2.

Hmm... I'm pretty sure it is one of the  MPEG-1 Audio Layers (there
are 3 of them, I believe)


> According to wikipedia:
>
> "It took some 9 months and one extra layer of codec complexity to turn
> MP2 into the well known MP3 format, by the introduction complementary
> signal processing tools, such as an additional MDCT transform, entropy
> coding and joint stereo mode (stereo intensity)."
>
> Whether there is any backwards compatibility is not clear to me from
> my reading so far. But if mp3 is another layer of complexity on top of
> mp2 then it stands to reason that an mp3 decoder may be able to decode
> and play an mp2 file.

It's not another layer of complexity, as much as it is another
specification for an audio stream that can co-exist (if you will) with
mpeg1 and mpeg2 streams (and for that matter, other architectures.)

>
>> Just google MPEG2 or MPEG-2
>
> we are not discussing mpeg2 except as a container. You will note my
> suggestion was to demux the .mp2 audio stream from the mpeg2 broadcast
> container and try playing the .mp2 stream in an mp3 player.

Ok, google MPEG1. But, they'll get you to the same places.

I thought that you wanted to just rename the file to mp3 and see if
the iPod could play it. I suppose it could if the ipod decoder was
capable of picking  the audio stream from the mpeg video file You
could certainly do it in linux and make an mp3 file to download.

Sorry for the confusion and the terse answer before.

You could visit the fraunhofer site to find out more about it:
http://www.iis.fraunhofer.de/EN/bf/amm/projects/index.jsp

Also: http://www.digital-audio.net/technical.shtml


brad