Re: [Discuss-gnuradio] [GSoC 17] DAB: Updates

[Marcus Müller]

Hi ben,

awesome! So, yeah, Felix wrote it as a GSoC project "back in the day", and thus, it contained the most important (or what he and his mentors considered most important) features first: and that was the AAC / LC encoder (which technically is MPEG4 HE AAC v1, as far as I understand). I don't know about the availability of free software encoders for xHE-AAC, but full HE AAC v1 and  v2 (which brings better music quality) should be available through Fraunhofer's FDK-AAC implementation – in fact, Luca's gr-dab DAB+ works use exactly that library (or rather, a fork of that library) for the audio encoding. If I remember correctly, Fraunhofer brought out FDK-AAC around the time Felix handed in his second milestone :)

So, if you'd want to wrap that, you'd be very much more than welcome! In fact, I'd head over to [1], and look at mp4_encode_sb , rip out the DAB+ specific parametrizations and put in the DRM specific ones (but I'm, alas, not aware which those are).

I think the frame lengths and stuff should be the same for AAC LC (only), HE AAC v1 (which is LC + the Spectral Band Replication SBR)  and v2 (v1+ Parametric Stereo), so, again, I //think// this is all a matter of swapping out the encoder and modifying a few metadata bits :)

Cheers,

Marcus

[1] https://github.com/kit-cel

On 19.08.2017 08:32, Benny Alexandar wrote:

Hi All,

Nice to see some discussion on DRM. Well, I also used gr-drm and is not fully supported like multiple audio and data services. DRm also uses tow audio codecs namely AAC and xHE-AAC. gr-drm supports only AAC. I don't know about any xHE-AAC encoder/decoder open source available. If anybody knows please let me know. I'm there to enhance the gr-drm to make it a fully blown DRM transmitter.

-ben

---

From: Benny Alexandar <address@hidden>
Sent: Saturday, August 19, 2017 10:30:23 AM
To: address@hidden
Subject: Re: [Discuss-gnuradio] [GSoC 17] DAB: Updates

 

Hi All,

Nice to see some discussion on DRM. Well, I also used gr-drm and is not fully supported like multiple audio and data services. DRm also uses tow audio codecs namely AAC and xHE-AAC. gr-drm supports only AAC. I don't know about any xHE-AAC encoder/decoder open source available. If anybody knows please let me know. I'm there to enhance the gr-drm to make it a fully blown DRM transmitter.

-ben

smime.p7s
Description: S/MIME Cryptographic Signature