rdesktop/rdpsnd_dsp.c

/*
   rdesktop: A Remote Desktop Protocol client.
   Sound DSP routines
   Copyright (C) Michael Gernoth 2006

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "rdesktop.h"
#include "rdpsnd.h"
#include "rdpsnd_dsp.h"

#define MAX_VOLUME 65535

static uint16 softvol_left = MAX_VOLUME;
static uint16 softvol_right = MAX_VOLUME;
static uint32 resample_to_srate = 44100;
static uint16 resample_to_bitspersample = 16;
static uint16 resample_to_channels = 2;

void
rdpsnd_dsp_softvol_set(uint16 left, uint16 right)
{
	softvol_left = left;
	softvol_right = right;
	DEBUG(("rdpsnd_dsp_softvol_set: left: %u, right: %u\n", left, right));
}

void
rdpsnd_dsp_softvol(unsigned char *buffer, unsigned int size, WAVEFORMATEX * format)
{
	unsigned int factor_left, factor_right;
	unsigned char *posin = buffer;
	unsigned char *posout = buffer;

	if ((softvol_left == MAX_VOLUME) && (softvol_right == MAX_VOLUME))
		return;

	factor_left = (softvol_left * 256) / MAX_VOLUME;
	factor_right = (softvol_right * 256) / MAX_VOLUME;

	if (format->nChannels == 1)
	{
		factor_left = factor_right = (factor_left + factor_right) / 2;
	}

	if (format->wBitsPerSample == 8)
	{
		sint8 val;

		while (posout < buffer + size)
		{
			/* Left */
			val = *posin++;
			val = (val * factor_left) >> 8;
			*posout++ = val;

			/* Right */
			val = *posin++;
			val = (val * factor_right) >> 8;
			*posout++ = val;
		}
	}
	else
	{
		sint16 val;

		while (posout < buffer + size)
		{
			/* Left */
			val = *posin++;
			val |= *posin++ << 8;
			val = (val * factor_left) >> 8;
			*posout++ = val & 0xff;
			*posout++ = val >> 8;

			/* Right */
			val = *posin++;
			val |= *posin++ << 8;
			val = (val * factor_right) >> 8;
			*posout++ = val & 0xff;
			*posout++ = val >> 8;
		}
	}

	DEBUG(("using softvol with factors left: %d, right: %d (%d/%d)\n", factor_left,
	       factor_right, format->wBitsPerSample, format->nChannels));
}

void
rdpsnd_dsp_swapbytes(unsigned char *buffer, unsigned int size, WAVEFORMATEX * format)
{
	int i;
	uint8 swap;

	if (format->wBitsPerSample == 8)
		return;

	for (i = 0; i < size; i += 2)
	{
		swap = *(buffer + i);
		*(buffer + i) = *(buffer + i + 1);
		*(buffer + i + 1) = swap;
	}
}

BOOL
rdpsnd_dsp_resample_set(uint32 device_srate, uint16 device_bitspersample, uint16 device_channels)
{
	if (device_srate != 44100 && device_srate != 22050)
		return False;

	if (device_bitspersample != 16 && device_bitspersample != 8)
		return False;

	if (device_channels != 1 && device_channels != 2)
		return False;

	resample_to_srate = device_srate;
	resample_to_bitspersample = device_bitspersample;
	resample_to_channels = device_channels;

	return True;
}

BOOL
rdpsnd_dsp_resample_supported(WAVEFORMATEX * format)
{
	if (format->wFormatTag != WAVE_FORMAT_PCM)
		return False;
	if ((format->nChannels != 1) && (format->nChannels != 2))
		return False;
	if ((format->wBitsPerSample != 8) && (format->wBitsPerSample != 16))
		return False;
	if ((format->nSamplesPerSec != 44100) && (format->nSamplesPerSec != 22050))
		return False;

	return True;
}

uint32
rdpsnd_dsp_resample(unsigned char **out, unsigned char *in, unsigned int size,
		    WAVEFORMATEX * format)
{
	static BOOL warned = False;
	int outsize, offset;
	int samplewidth = format->wBitsPerSample / 8;
	int i;

	if ((resample_to_bitspersample != format->wBitsPerSample) ||
	    (resample_to_channels != format->nChannels) ||
	    ((format->nSamplesPerSec != 44100) && (format->nSamplesPerSec != 22050)))
	{
		if (!warned)
		{
			warning("unsupported resample-settings (%u/%u/%u), not resampling!\n",
				format->nSamplesPerSec, format->wBitsPerSample, format->nChannels);
			warned = True;
		}
		return 0;
	}

	if (format->nSamplesPerSec == 22050)
	{
		outsize = size * 2;
		*out = xmalloc(outsize);

		/* Resample to 44100 */
		for (i = 0; i < (size / samplewidth); i++)
		{
			/* On a stereo-channel we must make sure that left and right
			   does not get mixed up, so we need to expand the sample-
			   data with channels in mind: 1234 -> 12123434
			   If we have a mono-channel, we can expand the data by simply
			   doubling the sample-data: 1234 -> 11223344 */
			if (resample_to_channels == 2)
				offset = ((i * 2) - (i & 1)) * samplewidth;
			else
				offset = (i * 2) * samplewidth;

			memcpy(*out + offset, in + (i * samplewidth), samplewidth);
			memcpy(*out + (resample_to_channels * samplewidth + offset),
			       in + (i * samplewidth), samplewidth);

		}
	}
	else
	{
		outsize = 0;
	}

	return outsize;
}

STREAM
rdpsnd_dsp_process(STREAM s, struct audio_driver * current_driver, WAVEFORMATEX * format)
{
	static struct stream out;

	/* softvol and byteswap do not change the amount of data they
	   return, so they can operate on the input-stream */
	if (current_driver->wave_out_volume == rdpsnd_dsp_softvol_set)
		rdpsnd_dsp_softvol(s->data, s->size, format);

#ifdef B_ENDIAN
	if (current_driver->need_byteswap_on_be)
		rdpsnd_dsp_swapbytes(s->data, s->size, format);
#endif

	out.data = NULL;

	if (current_driver->wave_out_format_supported == rdpsnd_dsp_resample_supported)
	{
		out.size = rdpsnd_dsp_resample(&out.data, s->data, s->size, format);
	}

	if (out.data == NULL)
	{
		out.data = xmalloc(s->size);
		memcpy(out.data, s->data, s->size);
		out.size = s->size;
	}

	out.p = out.data;
	out.end = out.p + out.size;

	return &out;
}