[Speex-dev] Decoded output buffer size
conrad at metadecks.org
Wed Apr 14 16:30:55 PDT 2010
On 14 April 2010 23:50, Daniele Barzotti
<daniele.barzotti at eurocomtel.com> wrote:
> Il 14/04/2010 14:37, Randy Yates wrote:
>> Usually a buffer is one frame of data, and a frame is 20 milliseconds.
>> Since the sample rate is typically 8 kHz in narrowband mode, this
>> corresponds to a buffer size of 160 samples.
> Hi Randy, thanks for the reply.
> So, suppose I encode an audio buffer (8000 kHz, MONO, float) of 640 PCM
> In output I have 4 speex frame of 20 byte each that I put in a RPT
> payload of 80 bytes:
> UINT CSpeexCodec::Encode( float *inBuff,
> const char**outBuff,
> UINT BufferFrames )
> while (BufferFrames>0)
> speex_encode(spx_state_, inBuff, &spx_bits_);
> nbBytes += speex_bits_write(&spx_bits_,
> inBuff+= spx_frame_size_;
> BufferFrames -= spx_frame_size_;
> ..nbBytes is 80 bytes..
> Now I send this packet over the network and, into the receiving side, I
> need to recreate the original PCM buffer (640 frames).
> But how can I know the size of each speex frame into a multiframe payload?
use speex_bit_read_from() just once on the packet, then call
speex_decode() once for each frame.
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