> Hi:
>
> Is it rational to compress video/audio -- for storing in a device with
> limited capacity or transferring on the internet via low-bandwidth
> connection -- using QAM?
>
> Has this ever been done before? If so, what did the resulting artifacts
> look/sound like?
You know many words, but few concepts. It is rational to compress milk
with comic books?
Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Reply by Ron N.●September 19, 20072007-09-19
On Sep 18, 10:50 pm, "Green Xenon [Radium]" <gluceg...@excite.com>
wrote:
> Hi:
>
> Is it rational to compress video/audio -- for storing in a device with
> limited capacity or transferring on the internet via low-bandwidth
> connection -- using QAM?
>
> Has this ever been done before?
I think some early digital cable transmission schemes
may have used QAM (Time-Warner's FSN over a decade ago).
Of course the video/audio data was precompressed using
an early form of MPEG to a low bit rate before, being
transport packetized and modulated back up in bandwidth
to fill one analog broadband channel.
Reply by Ron N.●September 19, 20072007-09-19
On Sep 18, 10:50 pm, "Green Xenon [Radium]" <gluceg...@excite.com>
> Is it rational to compress video/audio -- for storing in a device with
> limited capacity or transferring on the internet via low-bandwidth
> connection -- using QAM?
>
> Has this ever been done before?
Is it rational to XYZ for UVW using ABC? (for a random selection
of three parameters/technologies.) Possibly.
Especially if you don't mind sub-unity compression ratios.
Reply by Green Xenon [Radium]●September 19, 20072007-09-19
John Sampson wrote:
> Did you mean to say Vector Quantization instead of QAM? VQ has been used
> for audio and video codecs.
No
Reply by John Sampson●September 19, 20072007-09-19
Green Xenon [Radium] wrote:
> Hi:
>
> Is it rational to compress video/audio -- for storing in a device with
> limited capacity or transferring on the internet via low-bandwidth
> connection -- using QAM?
>
> Has this ever been done before? If so, what did the resulting artifacts
> look/sound like?
>
>
> Thanks,
>
> Radium
Did you mean to say Vector Quantization instead of QAM? VQ has been used
for audio and video codecs.
John
Reply by ●September 19, 20072007-09-19
On Sep 19, 1:50 am, "Green Xenon [Radium]" <gluceg...@excite.com>
wrote:
> Hi:
>
> Is it rational to compress video/audio -- for storing in a device with
> limited capacity or transferring on the internet via low-bandwidth
> connection -- using QAM?
>
> Has this ever been done before? If so, what did the resulting artifacts
> look/sound like?
>
> Thanks,
>
> Radium
QAM is not a compression scheme. It is a modulation scheme that maps a
group of input symbols to two quadrature amplitude values. In fact,
you'll find that it does the opposite of compression; the storage for
the two I/Q coefficients will likely take much more space than the
source data. Sure, you could just store a "symbol index" value, but
then you don't get any benefit over your original data size.
Jason
Reply by Green Xenon [Radium]●September 19, 20072007-09-19
Hi:
Is it rational to compress video/audio -- for storing in a device with
limited capacity or transferring on the internet via low-bandwidth
connection -- using QAM?
Has this ever been done before? If so, what did the resulting artifacts
look/sound like?
Thanks,
Radium