Skip to main content

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: Algorithm delay calculation for AAC LC for a 16khz stream? (Read 5973 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Algorithm delay calculation for AAC LC for a 16khz stream?

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

Algorithm delay calculation for AAC LC for a 16khz stream?

Reply #1
Just manually time align the two samples in an audio editor.

Algorithm delay calculation for AAC LC for a 16khz stream?

Reply #2
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

Algorithm delay calculation for AAC LC for a 16khz stream?

Reply #3
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.

Algorithm delay calculation for AAC LC for a 16khz stream?

Reply #4
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