src/amdtp.c - pub/scm/libs/ieee1394/libiec61883 - Git at Google

 /*
  * libiec61883 - Linux IEEE 1394 streaming media library.
  * Copyright (C) 2004 Kristian Hogsberg, Dan Dennedy, and Dan Maas.
  *
  * This file written by Kristian Hogsberg.
  * Update receive to use new raw1394 API by Dan Dennedy.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * This library 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
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */

 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif
 #include <stdio.h>
 #include <errno.h>
 #include <stdlib.h>
 #include <netinet/in.h>
 #include <assert.h>

 #include "iec61883.h"
 #include "iec61883-private.h"

 #define AMDTP_MAX_PACKET_SIZE 2048	//XXX: what is max packet size in AMDTP?

 iec61883_amdtp_t
 iec61883_amdtp_xmit_init (raw1394handle_t handle,
 		int rate,
 		int format,
 		int sample_format,
 		int mode,
 		int dimension,
 		iec61883_amdtp_xmit_t get_data, void *callback_data)
 {
 	int fdf, syt_interval;
 	struct iec61883_amdtp *amdtp;

 	amdtp = malloc (sizeof (struct iec61883_amdtp));
 	if (!amdtp) {
 		errno = ENOMEM;
 		return NULL;
 	}
 	amdtp->channel = -1;

 	if (format <= IEC61883_AMDTP_FORMAT_IEC958_AC3)
 		amdtp->format = format;
 	else {
 		free (amdtp);
 		return NULL;
 	}

 	switch (rate) {
 	case 32000:
 		syt_interval = 8;
 		fdf = IEC61883_FDF_SFC_32KHZ;
 		amdtp->iec958_rate_code = 0x0c;
 		break;
 	case 44100:
 		syt_interval = 8;
 		fdf = IEC61883_FDF_SFC_44K1HZ;
 		amdtp->iec958_rate_code = 0x00;
 		break;
 	case 48000:
 		syt_interval = 8;
 		fdf = IEC61883_FDF_SFC_48KHZ;
 		amdtp->iec958_rate_code = 0x04;
 		break;
 	case 88200:
 		syt_interval = 16;
 		fdf = IEC61883_FDF_SFC_88K2HZ;
 		amdtp->iec958_rate_code = 0x00;
 		break;
 	case 96000:
 		syt_interval = 16;
 		fdf = IEC61883_FDF_SFC_96KHZ;
 		amdtp->iec958_rate_code = 0x00;
 		break;
 	case 176400:
 		syt_interval = 32;
 		fdf = IEC61883_FDF_SFC_176K4HZ;
 		amdtp->iec958_rate_code = 0x00;
 		break;
 	case 192000:
 		syt_interval = 32;
 		fdf = IEC61883_FDF_SFC_192KHZ;
 		amdtp->iec958_rate_code = 0x00;
 		break;

 	default:
 		free (amdtp);
 		return NULL;
 	}

 	/* When using the AM824 raw subformat we can stream signals of
 	 * any dimension.  The IEC958 subformat, however, only
 	 * supports 2 channels.
 	 */
 	if (amdtp->format == IEC61883_AMDTP_FORMAT_IEC958_PCM && dimension > 2) {
 		free (amdtp);
 		return NULL;
 	}
 	else {
 		amdtp->dimension = dimension;
 	}

 	amdtp->sample_format = sample_format;
 	amdtp->get_data = get_data;
 	amdtp->callback_data = callback_data;
 	amdtp->handle = handle;
 	amdtp->dimension = dimension;
 	amdtp->buffer_packets = 1000;
 	amdtp->prebuffer_packets = 1000;
 	amdtp->irq_interval = 250;
 	amdtp->synch = 0;
 	amdtp->speed = RAW1394_ISO_SPEED_100;

 	iec61883_cip_init (&amdtp->cip, IEC61883_FMT_AMDTP, fdf,
 			   rate, dimension, syt_interval);
 	iec61883_cip_set_transmission_mode (&amdtp->cip, mode);

 	raw1394_set_userdata (handle, amdtp);

 	return amdtp;
 }

 static enum raw1394_iso_disposition
 amdtp_xmit_handler (raw1394handle_t handle,
 		unsigned char *data, unsigned int *len,
 		unsigned char *tag, unsigned char *sy,
 		int cycle, unsigned int dropped)
 {
 	struct iec61883_amdtp *amdtp = raw1394_get_userdata (handle);
 	struct iec61883_packet *packet = (struct iec61883_packet *) data;
 	int nevents = iec61883_cip_fill_header (handle, &amdtp->cip, packet);
 	quadlet_t *event = (quadlet_t *) packet->data;
 	enum raw1394_iso_disposition result = RAW1394_ISO_OK;
 	int nsamples;

 	assert (amdtp != NULL);
 	amdtp->total_dropped += dropped;

 	if (nevents > 0) {
 		nsamples = nevents;
 	}
 	else {
 		if (amdtp->cip.mode == IEC61883_MODE_BLOCKING_EMPTY) {
 			nsamples = 0;
 		}
 		else {
 			nsamples = amdtp->cip.syt_interval;
 		}
 	}

 	memset (packet->data, '\0', nsamples * amdtp->dimension * sizeof (quadlet_t));

 	if (nevents > 0) {
 		if( amdtp->get_data (amdtp, packet->data, nevents, packet->dbc, dropped,
 				     amdtp->callback_data) < 0 ) {
 			result = RAW1394_ISO_ERROR;
 		}
 	}

 	if (result == RAW1394_ISO_OK ) {
 		quadlet_t label = 0;
 		int i;

 		if (amdtp->format == IEC61883_AMDTP_FORMAT_RAW) {
 			label = IEC61883_AM824_LABEL;
 			switch (amdtp->sample_format) {
 				case IEC61883_AMDTP_INPUT_LE24:
 					label |= IEC61883_AM824_VBL_24BITS;
 					break;
 				case IEC61883_AMDTP_INPUT_LE20:
 					label |= IEC61883_AM824_VBL_20BITS;
 					break;
 				case IEC61883_AMDTP_INPUT_LE16:
 					label |= IEC61883_AM824_VBL_16BITS;
 					break;
 				default:
 					break;
 			}
 			label = label << 24;

 			for (i = 0; i < nsamples * amdtp->dimension; i++) {
 				event[i] = htonl (event[i] | label);
 			}
 		}
 		else if (amdtp->format == IEC61883_AMDTP_FORMAT_IEC958_PCM) {
 			struct iec60958_data *sample;

 			for (i = 0; i < nsamples * amdtp->dimension; i++) {
 				sample = (struct iec60958_data *) &event[i];
 				sample->label = IEC60958_LABEL;
 				if (nevents == 0) {
 					sample->validity = IEC60958_DATA_INVALID;
 					/* Using reseved value for old
 					 * SoftAcoustik SA2.0 speakers. */
 					sample->pac = IEC60958_PAC_RSV;
 				}
 				else {
 					sample->validity = IEC60958_DATA_VALID;
 					if( i % 2 == 0 || amdtp->dimension == 1 ) {
 						/* even --> CHANNEL 1 */
 						sample->pac = IEC60958_PAC_M;
 					}
 					else {
 						/* Odd --> CHANNEL 2 */
 						sample->pac = IEC60958_PAC_W;
 					}
 				}

 				/* The parity bit should be computed here... */
 				event[i] = htonl (event[i]);
 			}
 		}
 		else {
 			/* Unsupported format. */
 			result = RAW1394_ISO_ERROR;
 		}

 		*len = nsamples * amdtp->dimension * sizeof (quadlet_t) + 8;
 		*tag = IEC61883_TAG_WITH_CIP;
 		*sy = 0;
 	}

 	return result;
 }

 int
 iec61883_amdtp_xmit_start (struct iec61883_amdtp *amdtp, int channel)
 {
 	int result = 0;
 	unsigned int max_packet_size;

 	assert (amdtp != NULL);
 	max_packet_size = iec61883_cip_get_max_packet_size (&amdtp->cip);

 	result = raw1394_iso_xmit_init (amdtp->handle, amdtp_xmit_handler,
 					amdtp->buffer_packets,
 					max_packet_size, channel,
 					amdtp->speed, amdtp->irq_interval);
 	if (result == 0) {
 		amdtp->total_dropped = 0;
 		amdtp->channel = channel;
 		result = raw1394_iso_xmit_start (amdtp->handle, 0,
 						 amdtp->prebuffer_packets);
 	}

 	return result;
 }

 iec61883_amdtp_t
 iec61883_amdtp_recv_init (raw1394handle_t handle,
 		iec61883_amdtp_recv_t put_data, void *callback_data)
 {
 	struct iec61883_amdtp *amdtp;

 	amdtp = malloc (sizeof (struct iec61883_amdtp));
 	if (!amdtp) {
 		errno = ENOMEM;
 		return NULL;
 	}

 	amdtp->channel = -1;
 	amdtp->handle = handle;
 	amdtp->put_data = put_data;
 	amdtp->callback_data = callback_data;
 	amdtp->buffer_packets = 1000;
 	amdtp->prebuffer_packets = 1000;
 	amdtp->irq_interval = 250;
 	amdtp->synch = 0;

 	raw1394_set_userdata (handle, amdtp);

 	return amdtp;
 }

 static enum raw1394_iso_disposition
 amdtp_recv_handler (raw1394handle_t handle,
 		unsigned char *data,
 		unsigned int len,
 		unsigned char channel,
 		unsigned char tag,
 		unsigned char sy,
 		unsigned int cycle,
 		unsigned int dropped)
 {
 	struct iec61883_amdtp *amdtp = raw1394_get_userdata (handle);
 	enum raw1394_iso_disposition result = RAW1394_ISO_OK;
 	struct iec61883_packet *packet = (struct iec61883_packet *) data;
 	int label;

 	assert (amdtp != NULL);
 	amdtp->total_dropped += dropped;

 	/* We only support AM824 data for the moment. */
 	/* We should check the DBC value to make sure we don't miss any packet. */
 	if (tag == IEC61883_TAG_WITH_CIP &&
 	    packet->fmt == IEC61883_FMT_AMDTP && (
 	    ((packet->fdf & ~IEC61883_FDF_SFC_MASK) == IEC61883_FDF_AM824) ||
 	    ((packet->fdf & ~IEC61883_FDF_SFC_MASK) == IEC61883_FDF_AM824_CONTROLLED))) {

 		/* We fill amdtp structure fields upon reception of first packet. */
 		if ((amdtp->dimension < 0) && (packet->syt != 0xFFFF)) {
 			amdtp->dimension = packet->dbs; /* Number of audio channels. */

 			DEBUG ("FDF code = %d.", packet->fdf);

 			/* Obtaining sampling rate from SFC code. */
 			switch (packet->fdf & IEC61883_FDF_SFC_MASK)
 			{
 			case IEC61883_FDF_SFC_32KHZ:
 				amdtp->rate = 32000;
 				break;
 			case IEC61883_FDF_SFC_44K1HZ:
 				amdtp->rate = 44100;
 				break;
 			case IEC61883_FDF_SFC_48KHZ:
 				amdtp->rate = 48000;
 				break;
 			case IEC61883_FDF_SFC_88K2HZ:
 				amdtp->rate = 88200;
 				break;
 			case IEC61883_FDF_SFC_96KHZ:
 				amdtp->rate = 96000;
 				break;
 			case IEC61883_FDF_SFC_176K4HZ:
 				amdtp->rate = 176400;
 				break;
 			case IEC61883_FDF_SFC_192KHZ:
 				amdtp->rate = 192000;
 			default:
 				WARN ("Unsupported SFC code (%d).",
 				      packet->fdf & IEC61883_FDF_SFC_MASK);
 				return RAW1394_ISO_ERROR;
 			}

 			label = htonl (*((quadlet_t *) packet->data)) >> 24;

 			/* Checking label. */
 			if ((label & ~0x03) == IEC61883_AM824_LABEL) {
 				DEBUG ("Multi-bit Linear Audio (MBLA) samples.");
 				/* Multi-bit Linear Audio (MBLA). */
 				amdtp->format = IEC61883_AMDTP_FORMAT_RAW;

 				/* Checking Valid Bit Length code. */
 				switch (label & 0x03) {
 				case IEC61883_AM824_VBL_24BITS:
 					DEBUG ("24-bits samples.");
 					amdtp->sample_format =
 						IEC61883_AMDTP_INPUT_LE24;
 					break;
 				case IEC61883_AM824_VBL_20BITS:
 					DEBUG ("20-bits samples.");
 					amdtp->sample_format =
 						IEC61883_AMDTP_INPUT_LE20;
 					break;
 				case IEC61883_AM824_VBL_16BITS:
 					DEBUG ("16-bits samples.");
 					amdtp->sample_format =
 						IEC61883_AMDTP_INPUT_LE16;
 					break;
 				default:
 					WARN ("Unsupported valid bit length code (%d).", label & 0x03);
 					result = RAW1394_ISO_ERROR;
 				}
 			} else if ((label >= 0) && (label <= 0x3F)) {
 				/* IEC60958 Conformant Data. */
 				/* TODO: how to determine AC3 */
 				amdtp->format = IEC61883_AMDTP_FORMAT_IEC958_PCM;
 				amdtp->sample_format = IEC61883_AMDTP_INPUT_NA;
 			} else {
 				WARN ("Unsupported data format label (%d).",
 				      label);
 				result = RAW1394_ISO_ERROR;
 			}
 		}

 		if ((result == RAW1394_ISO_OK) &&
 				(amdtp->dimension > 0) && (packet->syt != 0xFFFF)) {
 			int nsamples = (len / sizeof (quadlet_t)) - 2; /* Substracting CIP headers. */
 			quadlet_t *event = (quadlet_t *) packet->data;
 			int i;

 			for (i = 0; i < nsamples; i++)
 				event[i] = ntohl (event[i]);

 			if (amdtp->put_data (amdtp, packet->data, nsamples, packet->dbc, dropped,
 				amdtp->callback_data) < 0)
 				result = RAW1394_ISO_ERROR;
 		}
 	}
 	if (result == RAW1394_ISO_OK && dropped)
 		result = RAW1394_ISO_DEFER;

 	return result;
 }

 int
 iec61883_amdtp_recv_start (struct iec61883_amdtp *amdtp, int channel)
 {
 	int result = 0;

 	assert (amdtp != NULL);
 	result = raw1394_iso_recv_init (amdtp->handle,
 		amdtp_recv_handler,
 		amdtp->buffer_packets,
 		AMDTP_MAX_PACKET_SIZE,
 		channel,
 		RAW1394_DMA_PACKET_PER_BUFFER,
 		amdtp->irq_interval);

 	if (result == 0) {
 		amdtp->total_dropped = 0;
 		amdtp->channel = channel;
 		amdtp->dimension = -1;	/* The audio informations in amdtp structure will be
 					 * filled-in upon reception of the first isochronous
 					 * packet. */

 		result = raw1394_iso_recv_start (amdtp->handle, -1, -1, 0);
 	}
 	return result;
 }

 void
 iec61883_amdtp_recv_stop (struct iec61883_amdtp *amdtp)
 {
 	assert (amdtp != NULL);
 	if (amdtp->synch)
 		raw1394_iso_recv_flush (amdtp->handle);
 	raw1394_iso_shutdown (amdtp->handle);
 }

 void
 iec61883_amdtp_xmit_stop (struct iec61883_amdtp *amdtp)
 {
 	assert (amdtp != NULL);
 	if (amdtp->synch)
 		raw1394_iso_xmit_sync (amdtp->handle);
 	raw1394_iso_shutdown (amdtp->handle);
 }

 void
 iec61883_amdtp_close (struct iec61883_amdtp *amdtp)
 {
 	assert (amdtp != NULL);
 	if (amdtp->put_data)
 		iec61883_amdtp_recv_stop (amdtp);
 	if (amdtp->get_data)
 		iec61883_amdtp_xmit_stop (amdtp);
 	free (amdtp);
 }

 unsigned int
 iec61883_amdtp_get_buffers (iec61883_amdtp_t amdtp)
 {
 	assert (amdtp != NULL);
 	return amdtp->buffer_packets;
 }

 void
 iec61883_amdtp_set_buffers (iec61883_amdtp_t amdtp, unsigned int packets)
 {
 	assert (amdtp != NULL);
 	amdtp->buffer_packets = packets;
 }

 unsigned int
 iec61883_amdtp_get_prebuffers (iec61883_amdtp_t amdtp)
 {
 	assert (amdtp != NULL);
 	return amdtp->prebuffer_packets;
 }

 void
 iec61883_amdtp_set_prebuffers (iec61883_amdtp_t amdtp, unsigned int packets)
 {
 	assert (amdtp != NULL);
 	amdtp->prebuffer_packets = packets;
 }

 unsigned int
 iec61883_amdtp_get_irq_interval (iec61883_amdtp_t amdtp)
 {
 	assert (amdtp != NULL);
 	return amdtp->irq_interval;
 }

 void
 iec61883_amdtp_set_irq_interval (iec61883_amdtp_t amdtp, unsigned int packets)
 {
 	assert (amdtp != NULL);
 	amdtp->irq_interval = packets;
 }

 int
 iec61883_amdtp_get_synch (iec61883_amdtp_t amdtp)
 {
 	assert (amdtp != NULL);
 	return amdtp->synch;
 }

 void
 iec61883_amdtp_set_synch (iec61883_amdtp_t amdtp, int synch)
 {
 	assert (amdtp != NULL);
 	amdtp->synch = synch;
 }

 int
 iec61883_amdtp_get_speed (iec61883_amdtp_t amdtp)
 {
 	assert (amdtp != NULL);
 	return amdtp->speed;
 }

 void
 iec61883_amdtp_set_speed (iec61883_amdtp_t amdtp, int speed)
 {
 	assert (amdtp != NULL);
 	amdtp->speed = speed;
 }

 unsigned int
 iec61883_amdtp_get_dropped(iec61883_amdtp_t amdtp)
 {
 	assert (amdtp != NULL);
 	return amdtp->total_dropped;
 }

 void *
 iec61883_amdtp_get_callback_data (iec61883_amdtp_t amdtp)
 {
 	assert (amdtp != NULL);
 	return amdtp->callback_data;
 }

 int
 iec61883_amdtp_get_dimension(iec61883_amdtp_t amdtp)
 {
 	assert (amdtp != NULL);
 	return amdtp->dimension;
 }

 int
 iec61883_amdtp_get_rate(iec61883_amdtp_t amdtp)
 {
 	assert (amdtp != NULL);
 	return amdtp->rate;
 }

 enum iec61883_amdtp_format
 iec61883_amdtp_get_format(iec61883_amdtp_t amdtp)
 {
 	assert (amdtp != NULL);
 	return amdtp->format;
 }

 enum iec61883_amdtp_sample_format
 iec61883_amdtp_get_sample_format(iec61883_amdtp_t amdtp)
 {
 	assert (amdtp != NULL);
 	return amdtp->sample_format;
 }
	/*
	* libiec61883 - Linux IEEE 1394 streaming media library.
	* Copyright (C) 2004 Kristian Hogsberg, Dan Dennedy, and Dan Maas.
	*
	* This file written by Kristian Hogsberg.
	* Update receive to use new raw1394 API by Dan Dennedy.
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation; either
	* version 2.1 of the License, or (at your option) any later version.
	*
	* This library 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
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with this library; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*/

	#ifdef HAVE_CONFIG_H
	#include <config.h>
	#endif
	#include <stdio.h>
	#include <errno.h>
	#include <stdlib.h>
	#include <netinet/in.h>
	#include <assert.h>

	#include "iec61883.h"
	#include "iec61883-private.h"

	#define AMDTP_MAX_PACKET_SIZE 2048 //XXX: what is max packet size in AMDTP?

	iec61883_amdtp_t
	iec61883_amdtp_xmit_init (raw1394handle_t handle,
	int rate,
	int format,
	int sample_format,
	int mode,
	int dimension,
	iec61883_amdtp_xmit_t get_data, void *callback_data)
	{
	int fdf, syt_interval;
	struct iec61883_amdtp *amdtp;

	amdtp = malloc (sizeof (struct iec61883_amdtp));
	if (!amdtp) {
	errno = ENOMEM;
	return NULL;
	}
	amdtp->channel = -1;

	if (format <= IEC61883_AMDTP_FORMAT_IEC958_AC3)
	amdtp->format = format;
	else {
	free (amdtp);
	return NULL;
	}

	switch (rate) {
	case 32000:
	syt_interval = 8;
	fdf = IEC61883_FDF_SFC_32KHZ;
	amdtp->iec958_rate_code = 0x0c;
	break;
	case 44100:
	syt_interval = 8;
	fdf = IEC61883_FDF_SFC_44K1HZ;
	amdtp->iec958_rate_code = 0x00;
	break;
	case 48000:
	syt_interval = 8;
	fdf = IEC61883_FDF_SFC_48KHZ;
	amdtp->iec958_rate_code = 0x04;
	break;
	case 88200:
	syt_interval = 16;
	fdf = IEC61883_FDF_SFC_88K2HZ;
	amdtp->iec958_rate_code = 0x00;
	break;
	case 96000:
	syt_interval = 16;
	fdf = IEC61883_FDF_SFC_96KHZ;
	amdtp->iec958_rate_code = 0x00;
	break;
	case 176400:
	syt_interval = 32;
	fdf = IEC61883_FDF_SFC_176K4HZ;
	amdtp->iec958_rate_code = 0x00;
	break;
	case 192000:
	syt_interval = 32;
	fdf = IEC61883_FDF_SFC_192KHZ;
	amdtp->iec958_rate_code = 0x00;
	break;

	default:
	free (amdtp);
	return NULL;
	}

	/* When using the AM824 raw subformat we can stream signals of
	* any dimension. The IEC958 subformat, however, only
	* supports 2 channels.
	*/
	if (amdtp->format == IEC61883_AMDTP_FORMAT_IEC958_PCM && dimension > 2) {
	free (amdtp);
	return NULL;
	}
	else {
	amdtp->dimension = dimension;
	}

	amdtp->sample_format = sample_format;
	amdtp->get_data = get_data;
	amdtp->callback_data = callback_data;
	amdtp->handle = handle;
	amdtp->dimension = dimension;
	amdtp->buffer_packets = 1000;
	amdtp->prebuffer_packets = 1000;
	amdtp->irq_interval = 250;
	amdtp->synch = 0;
	amdtp->speed = RAW1394_ISO_SPEED_100;

	iec61883_cip_init (&amdtp->cip, IEC61883_FMT_AMDTP, fdf,
	rate, dimension, syt_interval);
	iec61883_cip_set_transmission_mode (&amdtp->cip, mode);

	raw1394_set_userdata (handle, amdtp);

	return amdtp;
	}

	static enum raw1394_iso_disposition
	amdtp_xmit_handler (raw1394handle_t handle,
	unsigned char data, unsigned int len,
	unsigned char tag, unsigned char sy,
	int cycle, unsigned int dropped)
	{
	struct iec61883_amdtp *amdtp = raw1394_get_userdata (handle);
	struct iec61883_packet packet = (struct iec61883_packet ) data;
	int nevents = iec61883_cip_fill_header (handle, &amdtp->cip, packet);
	quadlet_t event = (quadlet_t ) packet->data;
	enum raw1394_iso_disposition result = RAW1394_ISO_OK;
	int nsamples;

	assert (amdtp != NULL);
	amdtp->total_dropped += dropped;

	if (nevents > 0) {
	nsamples = nevents;
	}
	else {
	if (amdtp->cip.mode == IEC61883_MODE_BLOCKING_EMPTY) {
	nsamples = 0;
	}
	else {
	nsamples = amdtp->cip.syt_interval;
	}
	}

	memset (packet->data, '\0', nsamples * amdtp->dimension * sizeof (quadlet_t));

	if (nevents > 0) {
	if( amdtp->get_data (amdtp, packet->data, nevents, packet->dbc, dropped,
	amdtp->callback_data) < 0 ) {
	result = RAW1394_ISO_ERROR;
	}
	}

	if (result == RAW1394_ISO_OK ) {
	quadlet_t label = 0;
	int i;

	if (amdtp->format == IEC61883_AMDTP_FORMAT_RAW) {
	label = IEC61883_AM824_LABEL;
	switch (amdtp->sample_format) {
	case IEC61883_AMDTP_INPUT_LE24:
	label \|= IEC61883_AM824_VBL_24BITS;
	break;
	case IEC61883_AMDTP_INPUT_LE20:
	label \|= IEC61883_AM824_VBL_20BITS;
	break;
	case IEC61883_AMDTP_INPUT_LE16:
	label \|= IEC61883_AM824_VBL_16BITS;
	break;
	default:
	break;
	}
	label = label << 24;

	for (i = 0; i < nsamples * amdtp->dimension; i++) {
	event[i] = htonl (event[i] \| label);
	}
	}
	else if (amdtp->format == IEC61883_AMDTP_FORMAT_IEC958_PCM) {
	struct iec60958_data *sample;

	for (i = 0; i < nsamples * amdtp->dimension; i++) {
	sample = (struct iec60958_data *) &event[i];
	sample->label = IEC60958_LABEL;
	if (nevents == 0) {
	sample->validity = IEC60958_DATA_INVALID;
	/* Using reseved value for old
	* SoftAcoustik SA2.0 speakers. */
	sample->pac = IEC60958_PAC_RSV;
	}
	else {
	sample->validity = IEC60958_DATA_VALID;
	if( i % 2 == 0 \|\| amdtp->dimension == 1 ) {
	/* even --> CHANNEL 1 */
	sample->pac = IEC60958_PAC_M;
	}
	else {
	/* Odd --> CHANNEL 2 */
	sample->pac = IEC60958_PAC_W;
	}
	}

	/* The parity bit should be computed here... */
	event[i] = htonl (event[i]);
	}
	}
	else {
	/* Unsupported format. */
	result = RAW1394_ISO_ERROR;
	}

	len = nsamples amdtp->dimension * sizeof (quadlet_t) + 8;
	*tag = IEC61883_TAG_WITH_CIP;
	*sy = 0;
	}

	return result;
	}

	int
	iec61883_amdtp_xmit_start (struct iec61883_amdtp *amdtp, int channel)
	{
	int result = 0;
	unsigned int max_packet_size;

	assert (amdtp != NULL);
	max_packet_size = iec61883_cip_get_max_packet_size (&amdtp->cip);

	result = raw1394_iso_xmit_init (amdtp->handle, amdtp_xmit_handler,
	amdtp->buffer_packets,
	max_packet_size, channel,
	amdtp->speed, amdtp->irq_interval);
	if (result == 0) {
	amdtp->total_dropped = 0;
	amdtp->channel = channel;
	result = raw1394_iso_xmit_start (amdtp->handle, 0,
	amdtp->prebuffer_packets);
	}

	return result;
	}

	iec61883_amdtp_t
	iec61883_amdtp_recv_init (raw1394handle_t handle,
	iec61883_amdtp_recv_t put_data, void *callback_data)
	{
	struct iec61883_amdtp *amdtp;

	amdtp = malloc (sizeof (struct iec61883_amdtp));
	if (!amdtp) {
	errno = ENOMEM;
	return NULL;
	}

	amdtp->channel = -1;
	amdtp->handle = handle;
	amdtp->put_data = put_data;
	amdtp->callback_data = callback_data;
	amdtp->buffer_packets = 1000;
	amdtp->prebuffer_packets = 1000;
	amdtp->irq_interval = 250;
	amdtp->synch = 0;

	raw1394_set_userdata (handle, amdtp);

	return amdtp;
	}

	static enum raw1394_iso_disposition
	amdtp_recv_handler (raw1394handle_t handle,
	unsigned char *data,
	unsigned int len,
	unsigned char channel,
	unsigned char tag,
	unsigned char sy,
	unsigned int cycle,
	unsigned int dropped)
	{
	struct iec61883_amdtp *amdtp = raw1394_get_userdata (handle);
	enum raw1394_iso_disposition result = RAW1394_ISO_OK;
	struct iec61883_packet packet = (struct iec61883_packet ) data;
	int label;

	assert (amdtp != NULL);
	amdtp->total_dropped += dropped;

	/* We only support AM824 data for the moment. */
	/* We should check the DBC value to make sure we don't miss any packet. */
	if (tag == IEC61883_TAG_WITH_CIP &&
	packet->fmt == IEC61883_FMT_AMDTP && (
	((packet->fdf & ~IEC61883_FDF_SFC_MASK) == IEC61883_FDF_AM824) \|\|
	((packet->fdf & ~IEC61883_FDF_SFC_MASK) == IEC61883_FDF_AM824_CONTROLLED))) {

	/* We fill amdtp structure fields upon reception of first packet. */
	if ((amdtp->dimension < 0) && (packet->syt != 0xFFFF)) {
	amdtp->dimension = packet->dbs; /* Number of audio channels. */

	DEBUG ("FDF code = %d.", packet->fdf);

	/* Obtaining sampling rate from SFC code. */
	switch (packet->fdf & IEC61883_FDF_SFC_MASK)
	{
	case IEC61883_FDF_SFC_32KHZ:
	amdtp->rate = 32000;
	break;
	case IEC61883_FDF_SFC_44K1HZ:
	amdtp->rate = 44100;
	break;
	case IEC61883_FDF_SFC_48KHZ:
	amdtp->rate = 48000;
	break;
	case IEC61883_FDF_SFC_88K2HZ:
	amdtp->rate = 88200;
	break;
	case IEC61883_FDF_SFC_96KHZ:
	amdtp->rate = 96000;
	break;
	case IEC61883_FDF_SFC_176K4HZ:
	amdtp->rate = 176400;
	break;
	case IEC61883_FDF_SFC_192KHZ:
	amdtp->rate = 192000;
	default:
	WARN ("Unsupported SFC code (%d).",
	packet->fdf & IEC61883_FDF_SFC_MASK);
	return RAW1394_ISO_ERROR;
	}

	label = htonl (((quadlet_t ) packet->data)) >> 24;

	/* Checking label. */
	if ((label & ~0x03) == IEC61883_AM824_LABEL) {
	DEBUG ("Multi-bit Linear Audio (MBLA) samples.");
	/* Multi-bit Linear Audio (MBLA). */
	amdtp->format = IEC61883_AMDTP_FORMAT_RAW;

	/* Checking Valid Bit Length code. */
	switch (label & 0x03) {
	case IEC61883_AM824_VBL_24BITS:
	DEBUG ("24-bits samples.");
	amdtp->sample_format =
	IEC61883_AMDTP_INPUT_LE24;
	break;
	case IEC61883_AM824_VBL_20BITS:
	DEBUG ("20-bits samples.");
	amdtp->sample_format =
	IEC61883_AMDTP_INPUT_LE20;
	break;
	case IEC61883_AM824_VBL_16BITS:
	DEBUG ("16-bits samples.");
	amdtp->sample_format =
	IEC61883_AMDTP_INPUT_LE16;
	break;
	default:
	WARN ("Unsupported valid bit length code (%d).", label & 0x03);
	result = RAW1394_ISO_ERROR;
	}
	} else if ((label >= 0) && (label <= 0x3F)) {
	/* IEC60958 Conformant Data. */
	/* TODO: how to determine AC3 */
	amdtp->format = IEC61883_AMDTP_FORMAT_IEC958_PCM;
	amdtp->sample_format = IEC61883_AMDTP_INPUT_NA;
	} else {
	WARN ("Unsupported data format label (%d).",
	label);
	result = RAW1394_ISO_ERROR;
	}
	}

	if ((result == RAW1394_ISO_OK) &&
	(amdtp->dimension > 0) && (packet->syt != 0xFFFF)) {
	int nsamples = (len / sizeof (quadlet_t)) - 2; /* Substracting CIP headers. */
	quadlet_t event = (quadlet_t ) packet->data;
	int i;

	for (i = 0; i < nsamples; i++)
	event[i] = ntohl (event[i]);

	if (amdtp->put_data (amdtp, packet->data, nsamples, packet->dbc, dropped,
	amdtp->callback_data) < 0)
	result = RAW1394_ISO_ERROR;
	}
	}
	if (result == RAW1394_ISO_OK && dropped)
	result = RAW1394_ISO_DEFER;

	return result;
	}

	int
	iec61883_amdtp_recv_start (struct iec61883_amdtp *amdtp, int channel)
	{
	int result = 0;

	assert (amdtp != NULL);
	result = raw1394_iso_recv_init (amdtp->handle,
	amdtp_recv_handler,
	amdtp->buffer_packets,
	AMDTP_MAX_PACKET_SIZE,
	channel,
	RAW1394_DMA_PACKET_PER_BUFFER,
	amdtp->irq_interval);

	if (result == 0) {
	amdtp->total_dropped = 0;
	amdtp->channel = channel;
	amdtp->dimension = -1; /* The audio informations in amdtp structure will be
	* filled-in upon reception of the first isochronous
	* packet. */

	result = raw1394_iso_recv_start (amdtp->handle, -1, -1, 0);
	}
	return result;
	}

	void
	iec61883_amdtp_recv_stop (struct iec61883_amdtp *amdtp)
	{
	assert (amdtp != NULL);
	if (amdtp->synch)
	raw1394_iso_recv_flush (amdtp->handle);
	raw1394_iso_shutdown (amdtp->handle);
	}

	void
	iec61883_amdtp_xmit_stop (struct iec61883_amdtp *amdtp)
	{
	assert (amdtp != NULL);
	if (amdtp->synch)
	raw1394_iso_xmit_sync (amdtp->handle);
	raw1394_iso_shutdown (amdtp->handle);
	}

	void
	iec61883_amdtp_close (struct iec61883_amdtp *amdtp)
	{
	assert (amdtp != NULL);
	if (amdtp->put_data)
	iec61883_amdtp_recv_stop (amdtp);
	if (amdtp->get_data)
	iec61883_amdtp_xmit_stop (amdtp);
	free (amdtp);
	}

	unsigned int
	iec61883_amdtp_get_buffers (iec61883_amdtp_t amdtp)
	{
	assert (amdtp != NULL);
	return amdtp->buffer_packets;
	}

	void
	iec61883_amdtp_set_buffers (iec61883_amdtp_t amdtp, unsigned int packets)
	{
	assert (amdtp != NULL);
	amdtp->buffer_packets = packets;
	}

	unsigned int
	iec61883_amdtp_get_prebuffers (iec61883_amdtp_t amdtp)
	{
	assert (amdtp != NULL);
	return amdtp->prebuffer_packets;
	}

	void
	iec61883_amdtp_set_prebuffers (iec61883_amdtp_t amdtp, unsigned int packets)
	{
	assert (amdtp != NULL);
	amdtp->prebuffer_packets = packets;
	}

	unsigned int
	iec61883_amdtp_get_irq_interval (iec61883_amdtp_t amdtp)
	{
	assert (amdtp != NULL);
	return amdtp->irq_interval;
	}

	void
	iec61883_amdtp_set_irq_interval (iec61883_amdtp_t amdtp, unsigned int packets)
	{
	assert (amdtp != NULL);
	amdtp->irq_interval = packets;
	}

	int
	iec61883_amdtp_get_synch (iec61883_amdtp_t amdtp)
	{
	assert (amdtp != NULL);
	return amdtp->synch;
	}

	void
	iec61883_amdtp_set_synch (iec61883_amdtp_t amdtp, int synch)
	{
	assert (amdtp != NULL);
	amdtp->synch = synch;
	}

	int
	iec61883_amdtp_get_speed (iec61883_amdtp_t amdtp)
	{
	assert (amdtp != NULL);
	return amdtp->speed;
	}

	void
	iec61883_amdtp_set_speed (iec61883_amdtp_t amdtp, int speed)
	{
	assert (amdtp != NULL);
	amdtp->speed = speed;
	}

	unsigned int
	iec61883_amdtp_get_dropped(iec61883_amdtp_t amdtp)
	{
	assert (amdtp != NULL);
	return amdtp->total_dropped;
	}

	void *
	iec61883_amdtp_get_callback_data (iec61883_amdtp_t amdtp)
	{
	assert (amdtp != NULL);
	return amdtp->callback_data;
	}

	int
	iec61883_amdtp_get_dimension(iec61883_amdtp_t amdtp)
	{
	assert (amdtp != NULL);
	return amdtp->dimension;
	}

	int
	iec61883_amdtp_get_rate(iec61883_amdtp_t amdtp)
	{
	assert (amdtp != NULL);
	return amdtp->rate;
	}

	enum iec61883_amdtp_format
	iec61883_amdtp_get_format(iec61883_amdtp_t amdtp)
	{
	assert (amdtp != NULL);
	return amdtp->format;
	}

	enum iec61883_amdtp_sample_format
	iec61883_amdtp_get_sample_format(iec61883_amdtp_t amdtp)
	{
	assert (amdtp != NULL);
	return amdtp->sample_format;
	}