[Speex-dev] speex with jitter buffer

[nomprenom]

I did some changes:
- instead of "pcm size" units, i'm back to ms units
- I put in the buffer 40 ms directly instead of 2*20
speex_jitter_put(&m_jitter, (char *)RFMessage->Data, SPEEX_SIZE_40MS,
CPSeqNumber * 40);

On the player thread, I call 2 times speex_jitter_get, the first one with a
ts of 0, the 2nd one with 20ms timestamp offset - then I play the pcm
buffer.
I now wait for the first jitter_put before to do a jitter_get.

So it seams to work now.

The only problem is there are many warnings such as :

warning: jitter buffer sees negative buffering, your code might be broken.
Value is  -80
warning: jitter buffer sees negative buffering, your code might be broken.
Value is  -120
warning: jitter buffer sees negative buffering, your code might be broken.
Value is  -80
warning: jitter buffer sees negative buffering, your code might be broken.
Value is  -80
etc..

How to fix this ?

thanks

On Sun, 24 Jan 2021 at 16:59, nomprenom <nomprenom at gmail.com> wrote:

> Hi,
> I can't understand how to implement my encoder/decoder with the jitter
> buffer. I hope someone can help me:
> I have 2 threads.
> Because I don't have yet the full environment (with the devices etc..),
> - I'm reading from thread1,
> - sending to the main thread,
> - write to a jitter buff,
> - from th2 : read from the jitter and play the data.
> (Tomorrow, this is a device which will send the main thread the speex data
> via RF - that's why I need to handle a jitter).
>
> thread 1:
> 1) read 640 bytes from pcm (=40ms) (my settings are 8khz/16bits le)
> 2) encode to 40 bytes of speex
> 3) send to main thread 40 bytes of speex
>
> main thread:
> 1) speex_jitter_put(20 first bytes of speex, counter * 640) // timestamp =
> 0, 640, 1280, etc..
> 2) speex_jitter_put(20 last bytes of speex, 320 + counter * 640) //
> timestamp = 320, 960, 1600, etc..
>
> thread 2:
> 1) speex_jitter_get(buffer, NULL)
> 2)  speex_jitter_get(buffer + 320, timestamp=320)
> 3) pcm_write(buffer, 640)
>
> Actually I can't hear anything. I tried many things without success. It's
> the most "stable" flow I found without seeing many warnings from the api
> (underrun, negative buffer, etc..)
> - in the main thread, I think speex_jitter_put always puts 20 ms, right ?
> (I initialized the buffer with an audio sampling rate of 8khz)
> - in the main thread, I don't know if it's ok to put directly 40ms of
> speex or if I need to put 2 * 20ms with a different timestamp for the 2nd
> - I don't know too well what the timestamp parameter is : is it a
> timestamp in ms ? I use now, after searching on the net, "pcm units" (320 =
> 20 ms/ 640 = 40ms)
> - in thread 2, I can't pcm_write 320 only else I see many "underrun"
> errors. I thought, at the beginning, to simply read from the jitter and
> play (320) and to do this 2 times.
>
> Any help will be appreciated.
>
> Thanks.
>
>
>
>
> On Mon, 18 Jan 2021 at 21:30, nomprenom <nomprenom at gmail.com> wrote:
>
>> Thank you Tristan for your answer.
>>
>> For now I took jitter.c and .h from dsp and added them to the makefile of
>> speex.
>> I also added speex_jitter_buffer.c and h from the sample into the lib.
>>
>>
>>
>> On Mon, 18 Jan 2021 at 20:30, Tristan Matthews <tmatth at videolan.org>
>> wrote:
>>
>>> Hi,
>>>
>>> On Mon, Jan 18, 2021 at 12:29 PM nomprenom <nomprenom at gmail.com> wrote:
>>> >
>>> > Hi,
>>> > I'd like to use the speex encode/decoder library with the speex jitter
>>> buffer.
>>> > I took, first, the project "speex" from
>>> https://gitlab.xiph.org/xiph/speex
>>> > There is a nice sample in the directory speex_client/ which is using
>>> speex_jitter_buffer.h which itself is using <speex/speex_jitter.h>
>>> > I couldn't find this include file in the project.
>>> >
>>> > I checked in the project speexDSP and found it.
>>> > I thought, maybe, speexDsp is the new "speex" because it's deprecated.
>>> >
>>> > The problem is, now, with speexDsp I can't find the "speex.h" header
>>> and can't find either the speex_decode_init(), speex_decoder_ctl() APIs.
>>> > It's only in the sampledec.c in the doc/ directory of speexdsp
>>> >
>>> > How can I use the speex decoder/encoder with the speex_jitter api
>>> together ?
>>>
>>> The Speex project has been split in 2, speex "the codec" (where you'll
>>> find the decode_init and decoder_ctl API) and speexdsp "the DSP
>>> library" where you'll find the jitter buffer API. The motivation was
>>> that users want to be able to use purely the codec without the DSP
>>> stuff and vice-versa.
>>>
>>> N.B. The most active/used project in speexdsp is the resampler, you
>>> may find jitterbuffer implementations elsewhere that are a better fit
>>> for your project.
>>>
>>> See:
>>> https://gitlab.xiph.org/xiph/speex
>>> https://gitlab.xiph.org/xiph/speexdsp
>>>
>>> Best,
>>> Tristan
>>>
>>
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