Talk:Adaptive Multi-Rate audio codec

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Conversion[edit]

Conversion from/to amr to mp3 wav etc...

Could we add a sub section on converting to and from .amr files preferably with a link(s) to external websites offering FREE, NON-VIRUS executables to do these conversions (I've failed to find one yet)

JamMan- 12th Oct 06

If you're looking for a free online amr converter, there's one here: http://www.convertfiles.com/ Probably not suitable to put in the main article though.

-Matt —Preceding unsigned comment added by 77.102.238.243 (talk) 08:28, 4 October 2010 (UTC)

License[edit]

Could we inform in the page about the licensing of AMR ? It looks very unclear to a lot of people (including me). (e.g. ffmpeg or videolan can't include the C code included in the amr reference specification made by 3gpp.) --- AlexandreDulaunoy 13:25, 1 February 2007 (UTC)


Time of Recording tagged?[edit]

Is there any chance the time a recording was made is embedded somewhere in the file itself?

Since that would mean recordings could be coordinated with a GPS track and geotagged... —Preceding unsigned comment added by MrRedwood (talkcontribs) 00:26, 14 October 2007 (UTC)

filtered to 200-3400 Hz?[edit]

Does anyone have a reference for this?

I was reading briefly in 3GPP TS 26.090 V7.0.0 (2007-06) (available at http://www.3gpp.org/ftp/Specs/html-info/26-series.htm) where it's stated in Section 5.1 that a high-pass filter with a cut-off frequency of 80 Hz is used. --Jonxon (talk) 22:59, 11 January 2008 (UTC)

Patent Issues[edit]

Are those software patents? It looks like it, but I know nothing, so if somebody could confirm this and make it clear it would be appreciated. 'Cause if I'm right, this article isn't giving a global view of the subject - as it's pretty much assuming that these patents are just as important as any other patents, whereas software patents aren't relevant in some countries. So making it clear would let people like me know. --PhiJ (talk) 14:50, 14 October 2008 (UTC)

Many of the patents are, in fact, European patents. --71.191.197.79 (talk) 18:44, 12 April 2011 (UTC)

Please, provide references to the patent numbers that cover AMR. Otherwise I will have to remove that this is a patented codec as there are no references to it. — Preceding unsigned comment added by 2.137.183.75 (talk) 16:00, 31 May 2012 (UTC)

Frame lengths?[edit]

Aren't the frame lengths just wrong for AMR-NB? —Preceding unsigned comment added by 192.16.134.69 (talk) 16:15, 22 January 2009 (UTC)

What the heck...[edit]

...is "toll quality audio"? It's presumably something important, as it's noted as starting at 7.4kbit in particular, but a/ I've never heard of it, b/ there's no article or cite link or any other explanation. 193.63.174.211 (talk) 08:55, 16 October 2013 (UTC)

It refers to a speech quality that is perceived as equal to that of a digital PSTN line. The "toll" in "toll quality" refers to the use of long-distance PSTN lines, for which the telcos charge a toll, see e.g. here. The long-distance telephone lines in question use the G.711 audio codec and have very low jitter, due to their time division multiplex (TDM) nature. Conquerist (talk) 17:37, 16 October 2013 (UTC)