Algorithm delay calculation for AAC LC for a 16khz stream?, Algorithm delay of aac lc encoder and decoder |
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Algorithm delay calculation for AAC LC for a 16khz stream?, Algorithm delay of aac lc encoder and decoder |
 Feb 8 2013, 15:44
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#1
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Group: Members Posts: 20 Joined: 29-May 06 Member No.: 31280  |
Hi Techies,
I want to measure the quality of my AAC-LC encoder for a particular stream @16khz sampling frequency. I had Encoded and decoded the stream with bitrate@32kbps,mono channel. As per my understanding,algorithm delay for a 48khz stream is 1024(1 frame delay by encoder)+512(half of that by decoder).I have a tool which can measure the quality of encoder for 44.1/48 khz stream. But, as i want to measure the quality of my encoder @16khz sampling fr,i had downsampled an 48khz stream to 16khz stream(using goldwave tool) and after processing(encoder+decoder) again i had upsampled the output to 48khz stream. I need to mention the algorithm delay(in terms of samples) to my quality measurement tool,but i am struck with calculation of algorithm delay in this scenario. Please throw some light on this issue... Thanks In Advance, satish |
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Feb 8 2013, 20:43
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#2
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 Group: Members Posts: 4138 Joined: 2-September 02 Member No.: 3264 |
Just manually time align the two samples in an audio editor.
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Feb 11 2013, 07:01
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#3
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Group: Members Posts: 20 Joined: 29-May 06 Member No.: 31280 |
QUOTE (saratoga @ Feb 8 2013, 13:43)  Just manually time align the two samples in an audio editor. I want to know the actual logic to calculate the delay introduced by encoder for an 16Khz input. Thanks & Regards, satish |
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Feb 11 2013, 11:50
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#4
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 Group: Developer Posts: 618 Joined: 6-December 08 From: Erlangen Germany Member No.: 64012 |
Search for the paper "A guideline to audio codec delay" by Manfred Lutzky et al. Was presented at an AES conference, I think, and might be available for free.
Chris -------------------- If I don't reply to your reply, it means I agree with you.
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Feb 15 2013, 08:08
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#5
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Group: Members Posts: 20 Joined: 29-May 06 Member No.: 31280 |
QUOTE (C.R.Helmrich @ Feb 11 2013, 04:50) Search for the paper "A guideline to audio codec delay" by Manfred Lutzky et al. Was presented at an AES conference, I think, and might be available for free. Chris Hi Chris, Thank you for your reply. Actually, already i had gone through that paper,but i didn't get any calculation for an 16khz sampling frequency input stream. AAC-LC delay calculations in that paper were w.r.t 48khz sampling fr stream. Can you please let me know what extra factor will come into picture when the input stream is @16khz sampling fr? Thanks & Regards, satish |
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Lo-Fi Version | Time is now: 26th May 2013 - 09:33 |
