[Tremor] Need information of any Ogg player implementation on tremor

[Timur Elzhov]

2009/12/28 Diptopal Basu <diptopal.basu at gmail.com>:

>      If I wanted to test the Tremor decoder , how would I do it , are
> there any test cases available . Actually the previous questions I
> have been putting are meant for this .
>
>    Assuming I wanted to test the codec on an API level , what should
> be my steps ? For that matter if I wanted to test out any decoder or
> the player using it , how should I test it . I am not aware of testing
> on this domain hence my question .

Take the example from libvorbis (that do use of floating-point), find
"decoder_example.c", then you need to slightly modify it for use with
Tremor. Find the line

while((samples=vorbis_synthesis_pcmout(&vd,&pcm))>0)

above you'll see the declaration of pointer to PCM array declared as float

float **pcm

replace with int:

int **pcm;

below find the line where value for that array is calculated:

int val=floor(mono[j]*32767.f+.5f);

replace it with

int val=CLIP_TO_15(mono[j]>>9);

CLIP_TO_15 define somewhere above as

static inline int CLIP_TO_15(int x)
{
	if (x < -32768) return -32768;
	if (x > 32767) return 32767;
	return x;
}

or, probably more optimal:

static inline int CLIP_TO_15(int x)
{
	unsigned int tmp = x + 32768;
	return (tmp < 65536) ? x : (tmp < (1<<31)) ? 32767 : -32768;
}

Then link that code against Tremor. Probably, some initialization
function's signature for Tremor is different from that for Vorbis, I
don't remember exactly, sorry. But it could trivially be fixed, by
adding '1' as argument. Please tell me if you experienced the similar
problem.

Timur