aplay.c

ALSA驱动的一些调试测试工具

		err = snd_pcm_hw_params_get_buffer_time_max(params,
							    &buffer_time, 0);
		assert(err >= 0);
		if (buffer_time > 500000)
			buffer_time = 500000;
	}
	if (period_time == 0 && period_frames == 0) {
		if (buffer_time > 0)
			period_time = buffer_time / 4;
		else
			period_frames = buffer_frames / 4;
	}
	if (period_time > 0)
		err = snd_pcm_hw_params_set_period_time_near(handle, params,
							     &period_time, 0);
	else
		err = snd_pcm_hw_params_set_period_size_near(handle, params,
							     &period_frames, 0);
	assert(err >= 0);
	if (buffer_time > 0) {
		err = snd_pcm_hw_params_set_buffer_time_near(handle, params,
							     &buffer_time, 0);
	} else {
		err = snd_pcm_hw_params_set_buffer_size_near(handle, params,
							     &buffer_frames);
	}
	assert(err >= 0);
	err = snd_pcm_hw_params(handle, params);
	if (err < 0) {
		error(_("Unable to install hw params:"));
		snd_pcm_hw_params_dump(params, log);
		exit(EXIT_FAILURE);
	}
	snd_pcm_hw_params_get_period_size(params, &chunk_size, 0);
	snd_pcm_hw_params_get_buffer_size(params, &buffer_size);
	if (chunk_size == buffer_size) {
		error(_("Can't use period equal to buffer size (%lu == %lu)"),
		      chunk_size, buffer_size);
		exit(EXIT_FAILURE);
	}
	snd_pcm_sw_params_current(handle, swparams);
	if (avail_min < 0)
		n = chunk_size;
	else
		n = (double) rate * avail_min / 1000000;
	err = snd_pcm_sw_params_set_avail_min(handle, swparams, n);

	/* round up to closest transfer boundary */
	n = buffer_size;
	if (start_delay <= 0) {
		start_threshold = n + (double) rate * start_delay / 1000000;
	} else
		start_threshold = (double) rate * start_delay / 1000000;
	if (start_threshold < 1)
		start_threshold = 1;
	if (start_threshold > n)
		start_threshold = n;
	err = snd_pcm_sw_params_set_start_threshold(handle, swparams, start_threshold);
	assert(err >= 0);
	if (stop_delay <= 0) 
		stop_threshold = buffer_size + (double) rate * stop_delay / 1000000;
	else
		stop_threshold = (double) rate * stop_delay / 1000000;
	err = snd_pcm_sw_params_set_stop_threshold(handle, swparams, stop_threshold);
	assert(err >= 0);

	if (snd_pcm_sw_params(handle, swparams) < 0) {
		error(_("unable to install sw params:"));
		snd_pcm_sw_params_dump(swparams, log);
		exit(EXIT_FAILURE);
	}

	if (verbose)
		snd_pcm_dump(handle, log);

	bits_per_sample = snd_pcm_format_physical_width(hwparams.format);
	bits_per_frame = bits_per_sample * hwparams.channels;
	chunk_bytes = chunk_size * bits_per_frame / 8;
	audiobuf = realloc(audiobuf, chunk_bytes);
	if (audiobuf == NULL) {
		error(_("not enough memory"));
		exit(EXIT_FAILURE);
	}
	// fprintf(stderr, "real chunk_size = %i, frags = %i, total = %i\n", chunk_size, setup.buf.block.frags, setup.buf.block.frags * chunk_size);

	/* stereo VU-meter isn't always available... */
	if (vumeter == VUMETER_STEREO) {
		if (hwparams.channels != 2 || !interleaved || verbose > 2)
			vumeter = VUMETER_MONO;
	}

	/* show mmap buffer arragment */
	if (mmap_flag && verbose) {
		const snd_pcm_channel_area_t *areas;
		snd_pcm_uframes_t offset;
		int i;
		err = snd_pcm_mmap_begin(handle, &areas, &offset, &chunk_size);
		if (err < 0) {
			error("snd_pcm_mmap_begin problem: %s", snd_strerror(err));
			exit(EXIT_FAILURE);
		}
		for (i = 0; i < hwparams.channels; i++)
			fprintf(stderr, "mmap_area[%i] = %p,%u,%u (%u)\n", i, areas[i].addr, areas[i].first, areas[i].step, snd_pcm_format_physical_width(hwparams.format));
		/* not required, but for sure */
		snd_pcm_mmap_commit(handle, offset, 0);
	}

	buffer_frames = buffer_size;	/* for position test */
}

#ifndef timersub
#define	timersub(a, b, result) \
do { \
	(result)->tv_sec = (a)->tv_sec - (b)->tv_sec; \
	(result)->tv_usec = (a)->tv_usec - (b)->tv_usec; \
	if ((result)->tv_usec < 0) { \
		--(result)->tv_sec; \
		(result)->tv_usec += 1000000; \
	} \
} while (0)
#endif

/* I/O error handler */
static void xrun(void)
{
	snd_pcm_status_t *status;
	int res;
	
	snd_pcm_status_alloca(&status);
	if ((res = snd_pcm_status(handle, status))<0) {
		error(_("status error: %s"), snd_strerror(res));
		exit(EXIT_FAILURE);
	}
	if (snd_pcm_status_get_state(status) == SND_PCM_STATE_XRUN) {
		struct timeval now, diff, tstamp;
		gettimeofday(&now, 0);
		snd_pcm_status_get_trigger_tstamp(status, &tstamp);
		timersub(&now, &tstamp, &diff);
		fprintf(stderr, _("%s!!! (at least %.3f ms long)\n"),
			stream == SND_PCM_STREAM_PLAYBACK ? _("underrun") : _("overrun"),
			diff.tv_sec * 1000 + diff.tv_usec / 1000.0);
		if (verbose) {
			fprintf(stderr, _("Status:\n"));
			snd_pcm_status_dump(status, log);
		}
		if ((res = snd_pcm_prepare(handle))<0) {
			error(_("xrun: prepare error: %s"), snd_strerror(res));
			exit(EXIT_FAILURE);
		}
		return;		/* ok, data should be accepted again */
	} if (snd_pcm_status_get_state(status) == SND_PCM_STATE_DRAINING) {
		if (verbose) {
			fprintf(stderr, _("Status(DRAINING):\n"));
			snd_pcm_status_dump(status, log);
		}
		if (stream == SND_PCM_STREAM_CAPTURE) {
			fprintf(stderr, _("capture stream format change? attempting recover...\n"));
			if ((res = snd_pcm_prepare(handle))<0) {
				error(_("xrun(DRAINING): prepare error: %s"), snd_strerror(res));
				exit(EXIT_FAILURE);
			}
			return;
		}
	}
	if (verbose) {
		fprintf(stderr, _("Status(R/W):\n"));
		snd_pcm_status_dump(status, log);
	}
	error(_("read/write error, state = %s"), snd_pcm_state_name(snd_pcm_status_get_state(status)));
	exit(EXIT_FAILURE);
}

/* I/O suspend handler */
static void suspend(void)
{
	int res;

	if (!quiet_mode)
		fprintf(stderr, _("Suspended. Trying resume. ")); fflush(stderr);
	while ((res = snd_pcm_resume(handle)) == -EAGAIN)
		sleep(1);	/* wait until suspend flag is released */
	if (res < 0) {
		if (!quiet_mode)
			fprintf(stderr, _("Failed. Restarting stream. ")); fflush(stderr);
		if ((res = snd_pcm_prepare(handle)) < 0) {
			error(_("suspend: prepare error: %s"), snd_strerror(res));
			exit(EXIT_FAILURE);
		}
	}
	if (!quiet_mode)
		fprintf(stderr, _("Done.\n"));
}

static void print_vu_meter_mono(int perc, int maxperc)
{
	const int bar_length = 50;
	char line[80];
	int val;

	for (val = 0; val <= perc * bar_length / 100 && val < bar_length; val++)
		line[val] = '#';
	for (; val <= maxperc * bar_length / 100 && val < bar_length; val++)
		line[val] = ' ';
	line[val] = '+';
	for (++val; val <= bar_length; val++)
		line[val] = ' ';
	if (maxperc > 99)
		sprintf(line + val, "| MAX");
	else
		sprintf(line + val, "| %02i%%", maxperc);
	fputs(line, stdout);
	if (perc > 100)
		printf(_(" !clip  "));
}

static void print_vu_meter_stereo(int *perc, int *maxperc)
{
	const int bar_length = 35;
	char line[80];
	int c;

	memset(line, ' ', sizeof(line) - 1);
	line[bar_length + 3] = '|';

	for (c = 0; c < 2; c++) {
		int p = perc[c] * bar_length / 100;
		char tmp[4];
		if (p > bar_length)
			p = bar_length;
		if (c)
			memset(line + bar_length + 6 + 1, '#', p);
		else
			memset(line + bar_length - p - 1, '#', p);
		p = maxperc[c] * bar_length / 100;
		if (p > bar_length)
			p = bar_length;
		if (c)
			line[bar_length + 6 + 1 + p] = '+';
		else
			line[bar_length - p - 1] = '+';
		if (maxperc[c] > 99)
			sprintf(tmp, "MAX");
		else
			sprintf(tmp, "%02d%%", maxperc[c]);
		if (c)
			memcpy(line + bar_length + 3 + 1, tmp, 3);
		else
			memcpy(line + bar_length, tmp, 3);
	}
	line[bar_length * 2 + 6 + 2] = 0;
	fputs(line, stdout);
}

static void print_vu_meter(signed int *perc, signed int *maxperc)
{
	if (vumeter == VUMETER_STEREO)
		print_vu_meter_stereo(perc, maxperc);
	else
		print_vu_meter_mono(*perc, *maxperc);
}

/* peak handler */
static void compute_max_peak(u_char *data, size_t count)
{
	signed int val, max, perc[2], max_peak[2];
	static	int	run = 0;
	size_t ocount = count;
	int	format_little_endian = snd_pcm_format_little_endian(hwparams.format);	
	int ichans, c;

	if (vumeter == VUMETER_STEREO)
		ichans = 2;
	else
		ichans = 1;

	memset(max_peak, 0, sizeof(max_peak));
	switch (bits_per_sample) {
	case 8: {
		signed char *valp = (signed char *)data;
		signed char mask = snd_pcm_format_silence(hwparams.format);
		c = 0;
		while (count-- > 0) {
			val = *valp++ ^ mask;
			val = abs(val);
			if (max_peak[c] < val)
				max_peak[c] = val;
			if (vumeter == VUMETER_STEREO)
				c = !c;
		}
		break;
	}
	case 16: {
		signed short *valp = (signed short *)data;
		signed short mask = snd_pcm_format_silence_16(hwparams.format);
		signed short sval;

		count /= 2;
		c = 0;
		while (count-- > 0) {
			if (format_little_endian)
				sval = __le16_to_cpu(*valp);
			else
				sval = __be16_to_cpu(*valp);
			sval = abs(sval) ^ mask;
			if (max_peak[c] < sval)
				max_peak[c] = sval;
			valp++;
			if (vumeter == VUMETER_STEREO)
				c = !c;
		}
		break;
	}
	case 24: {
		unsigned char *valp = data;
		signed int mask = snd_pcm_format_silence_32(hwparams.format);

		count /= 3;
		c = 0;
		while (count-- > 0) {
			if (format_little_endian) {
				val = valp[0] | (valp[1]<<8) | (valp[2]<<16);
			} else {
				val = (valp[0]<<16) | (valp[1]<<8) | valp[2];
			}
			/* Correct signed bit in 32-bit value */
			if (val & (1<<(bits_per_sample-1))) {
				val |= 0xff<<24;	/* Negate upper bits too */
			}
			val = abs(val) ^ mask;
			if (max_peak[c] < val)
				max_peak[c] = val;
			valp += 3;
			if (vumeter == VUMETER_STEREO)
				c = !c;
		}
		break;
	}
	case 32: {
		signed int *valp = (signed int *)data;
		signed int mask = snd_pcm_format_silence_32(hwparams.format);

		count /= 4;
		c = 0;
		while (count-- > 0) {
			if (format_little_endian)
				val = __le32_to_cpu(*valp);
			else
				val = __be32_to_cpu(*valp);
			val = abs(val) ^ mask;
			if (max_peak[c] < val)
				max_peak[c] = val;
			valp++;
			if (vumeter == VUMETER_STEREO)
				c = !c;
		}
		break;
	}
	default:
		if (run == 0) {
			fprintf(stderr, _("Unsupported bit size %d.\n"), (int)bits_per_sample);
			run = 1;
		}
		return;
	}
	max = 1 << (bits_per_sample-1);
	if (max <= 0)
		max = 0x7fffffff;

	for (c = 0; c < ichans; c++) {
		if (bits_per_sample > 16)
			perc[c] = max_peak[c] / (max / 100);
		else
			perc[c] = max_peak[c] * 100 / max;
	}

	if (interleaved && verbose <= 2) {
		static int maxperc[2];
		static time_t t=0;
		const time_t tt=time(NULL);
		if(tt>t) {
			t=tt;
			maxperc[0] = 0;
			maxperc[1] = 0;
		}
		for (c = 0; c < ichans; c++)
			if (perc[c] > maxperc[c])
				maxperc[c] = perc[c];

		putchar('\r');
		print_vu_meter(perc, maxperc);
		fflush(stdout);
	}
	else if(verbose==3) {
		printf(_("Max peak (%li samples): 0x%08x "), (long)ocount, max_peak[0]);
		for (val = 0; val < 20; val++)
			if (val <= perc[0] / 5)
				putchar('#');
			else
				putchar(' ');
		printf(" %i%%\n", perc[0]);
		fflush(stdout);
	}
}

static void do_test_position(void)
{
	static int counter = 0;
	snd_pcm_sframes_t avail, delay;
	int err;

	err = snd_pcm_avail_delay(handle, &avail, &delay);
	if (err < 0)
		return;
	if (avail > 4 * (snd_pcm_sframes_t)buffer_frames ||
	    avail < -4 * (snd_pcm_sframes_t)buffer_frames ||
	    delay > 4 * (snd_pcm_sframes_t)buffer_frames ||
	    delay < -4 * (snd_pcm_sframes_t)buffer_frames) {
	  fprintf(stderr, "Suspicious buffer position (%i total): avail = %li, delay = %li, buffer = %li\n", ++counter, (long)avail, (long)delay, (long)buffer_frames);
	} else if (verbose) {
	  fprintf(stderr, "Buffer position: %li/%li (%li)\n", (long)avail, (long)delay, (long)buffer_frames);
	}
}

/*
 *  write function
 */

static ssize_t pcm_write(u_char *data, size_t count)
{
	ssize_t r;
	ssize_t result = 0;

	if (count < chunk_size) {
		snd_pcm_format_set_silence(hwparams.format, data + count * bits_per_frame / 8, (chunk_size - count) * hwparams.channels);
		count = chunk_size;
	}
	while (count > 0) {
		if (test_position)
			do_test_position();
		r = writei_func(handle, data, count);
		if (test_position)
			do_test_position();
		if (r == -EAGAIN || (r >= 0 && (size_t)r < count)) {
			snd_pcm_wait(handle, 1000);
		} else if (r == -EPIPE) {
			xrun();
		} else if (r == -ESTRPIPE) {
			suspend();
		} else if (r < 0) {
			error(_("write error: %s"), snd_strerror(r));
			exit(EXIT_FAILURE);
		}
		if (r > 0) {
			if (vumeter)
				compute_max_peak(data, r * hwparams.channels);
			result += r;
			count -= r;
			data += r * bits_per_frame / 8;
		}
	}
	return result;
}

static ssize_t pcm_writev(u_char **data, unsigned int channels, size_t count)
{
	ssize_t r;
	size_t result = 0;

	if (count != chunk_size) {
		unsigned int channel;
		size_t offset = count;
		size_t remaining = chunk_size - count;
		for (channel = 0; channel < channels; channel++)
			snd_pcm_format_set_silence(hwparams.format, data[channel] + offset * bits_per_sample / 8, remaining);
		count = chunk_size;
	}
	while (count > 0) {
		unsigned int channel;
		void *bufs[channels];
		size_t offset = result;
		for (channel = 0; channel < channels; channel++)
			bufs[channel] = data[channel] + offset * bits_per_sample / 8;
		if (test_position)
			do_test_position();
		r = writen_func(handle, bufs, count);
		if (test_position)
			do_test_position();
		if (r == -EAGAIN || (r >= 0 && (size_t)r < count)) {
			snd_pcm_wait(handle, 1000);
		} else if (r == -EPIPE) {
			xrun();
		} else if (r == -ESTRPIPE) {
			suspend();
		} else if (r < 0) {
			error(_("writev error: %s"), snd_strerror(r));
			exit(EXIT_FAILURE);