Subject: Re: [codec] codec tandeming/codec-requirements

From: Michael Knappe <[email-masked]>
Date: Mon, 9 Nov 2009 11:11:50 -0800

Having not heard any further comments on this thread, are we in consensus with the text as refined below? This would be an addition to section 5.8 (Legacy compatibility) in the next revision of draft-valin-codec-requirements.

Cheers,

Mike

On 10/26/09 1:58 PM, "Michael Knappe" <[email-masked]> wrote:

For ease of reading, incorporating the edits it would read as:

The systems providing input to the encoder and receiving output from the decoder may be far from ideal in actual use.  Input and output audio streams may be corrupted by compounding non-linear artifacts from analog hardware and digital processing. The codecs to be developed should be tested to ensure that they degrade gracefully under adverse audio conditions.  Types of digital corruption that may be tested include tandem encoding with similar and different codecs, low-quality resampling, and digital clipping.  Types of analog corruption that may be tested include microphones with substantial background noise, analog clipping, and loudspeaker distortion. No specific end-to-end quality requirements are mandated for use with the proposed codec. It is advisable, however, that several typical in-situ environments/processing chains be specified for the purpose of benchmarking end-to-end quality with the proposed codec.

On 10/26/09 1:47 PM, "Michael Knappe" <[email-masked]> wrote:

Benjamin,

Well worded paragraph, thanks. I would add just some minor edits and a scoping sentence at the end. My proposed changes are in italics.

Cheers,

Mike

Audio Corruption Robustness

The systems providing input to the encoder and s//receiving/ output from the decoder s/are
likely to/may/ be far from ideal in actual use.  Input and output audio streams
may be corrupted by s//compounding non-linear/ artifacts from analog hardware and digital processing. The codecs to be developed should be tested to ensure that they degrade
gracefully under adverse audio conditions.  Types of digital corruption
that may be tested include tandem encoding with similar and different
codecs, low-quality resampling, and digital clipping.  Types of analog
corruption that may be tested include microphones with substantial
background noise, analog clipping, and loudspeaker distortion. s//No specific end-to-end quality requirements are mandated for use with the proposed codec. It is advisable, however, that several typical in-situ environments/processing chains be specified for the purpose of benchmarking end-to-end quality with the proposed codec./
"""

"

On 10/23/09 6:29 AM, "Benjamin M. Schwartz" <[email-masked]> wrote:

Slava Borilin wrote:
> Henry, e2e (or p2p) is cool but what about Legal interception for
> example in this case, which every cellco has to implemenet?

Whether or not we want to encourage it, interception of VoIP traffic does
not require a re-encode.  The encoded packets can just be copied to the
additional receiver.

To address the "tandeming" issue, I think the following text should be
added to the "Basic Requirements" or "Additional Considerations":

"""
Audio Corruption Robustness

The systems providing input to the encoder and output from the decoder are
likely to be far from ideal in actual use.  Input and output audio streams
may be corrupted by artifacts from analog hardware and digital processing.
 The codecs to be developed should be tested to ensure that they degrade
gracefully under adverse audio conditions.  Types of digital corruption
that may be tested include tandem encoding with similar and different
codecs, low-quality resampling, and digital clipping.  Types of analog
corruption that may be tested include microphones with substantial
background noise, analog clipping, and loudspeaker distortion.
"""

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