SV: [Speex-dev] Symbian and buffer of 4096 bytes

[Jonas Tärnström]

I would consider another solution to your problem.

1) Save the 256 bytes, wait for 64 more in the next 4096 buffer and give
speex a complete frame.

Or...

2) Not sure on this but I believe simply dropping the 13:th frame could
be an option. < 10% packetloss is barely audible with correct decoding
and playback.

//JT




-----Ursprungligt meddelande-----
Från: speex-dev-bounces at xiph.org [mailto:speex-dev-bounces at xiph.org] För
Maurizio Cembalo
Skickat: den 13 april 2007 18:30
Till: speex-dev at xiph.org
Ämne: [Speex-dev] Symbian and buffer of 4096 bytes

I'm using speex under symbian (8000 hz, 16 bit) narrow band.
The phones API only give me a buffer of 4096 bytes in recording.To
reproduce audio I must fill up the buffer of the same dimension. 4096
isn't a multiple of 320.

I want encode the audio in streaming.

The solution that I adopt to encode is:
- Divide 4096-256 bytes in 12 frames of 320 bytes.
- Therefore the frame number 13 is composed only of 256 bytes.

I encode every frame and I fill up the last frame (13th) with 0 to
reach 160 samples.
I'm not sure, but it seems a low degradation but wish to know if it is
due to Speex or to the phone...
i'd like to know if the zeroes-padding i use could affect the encoder
in term of audio quality and, most of all, performance.


Regards,
maurizio

PS: I compile it with FIXED_POINT 1 and ARM4_ASM
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