/*
* Copyright (C) 2003-2014 The Music Player Daemon Project
* http://www.musicpd.org
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/** \file
*
* This filter copies audio data between channels. Useful for
* upmixing mono/stereo audio to surround speaker configurations.
*
* Its configuration consists of a "filter" section with a single
* "routes" entry, formatted as: \\
* routes "0>1, 1>0, 2>2, 3>3, 3>4" \\
* where each pair of numbers signifies a set of channels.
* Each source>dest pair leads to the data from channel #source
* being copied to channel #dest in the output.
*
* Example: \\
* routes "0>0, 1>1, 0>2, 1>3"\\
* upmixes stereo audio to a 4-speaker system, copying the front-left
* (0) to front left (0) and rear left (2), copying front-right (1) to
* front-right (1) and rear-right (3).
*
* If multiple sources are copied to the same destination channel, only
* one of them takes effect.
*/
#include "config.h"
#include "config/ConfigError.hxx"
#include "config/ConfigData.hxx"
#include "AudioFormat.hxx"
#include "filter/FilterPlugin.hxx"
#include "filter/FilterInternal.hxx"
#include "filter/FilterRegistry.hxx"
#include "pcm/PcmBuffer.hxx"
#include "util/StringUtil.hxx"
#include "util/Error.hxx"
#include "util/ConstBuffer.hxx"
#include <algorithm>
#include <assert.h>
#include <string.h>
#include <stdint.h>
#include <stdlib.h>
class RouteFilter final : public Filter {
/**
* The minimum number of channels we need for output
* to be able to perform all the copies the user has specified
*/
unsigned min_output_channels;
/**
* The minimum number of input channels we need to
* copy all the data the user has requested. If fewer
* than this many are supplied by the input, undefined
* copy operations are given zeroed sources in stead.
*/
unsigned min_input_channels;
/**
* The set of copy operations to perform on each sample
* The index is an output channel to use, the value is
* a corresponding input channel from which to take the
* data. A -1 means "no source"
*/
int8_t sources[MAX_CHANNELS];
/**
* The actual input format of our signal, once opened
*/
AudioFormat input_format;
/**
* The decided upon output format, once opened
*/
AudioFormat output_format;
/**
* The size, in bytes, of each multichannel frame in the
* input buffer
*/
size_t input_frame_size;
/**
* The size, in bytes, of each multichannel frame in the
* output buffer
*/
size_t output_frame_size;
/**
* The output buffer used last time around, can be reused if the size doesn't differ.
*/
PcmBuffer output_buffer;
public:
/**
* Parse the "routes" section, a string on the form
* a>b, c>d, e>f, ...
* where a... are non-unique, non-negative integers
* and input channel a gets copied to output channel b, etc.
* @param param the configuration block to read
* @param filter a route_filter whose min_channels and sources[] to set
* @return true on success, false on error
*/
bool Configure(const config_param ¶m, Error &error);
virtual AudioFormat Open(AudioFormat &af, Error &error) override;
virtual void Close();
virtual ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
Error &error) override;
};
bool
RouteFilter::Configure(const config_param ¶m, Error &error) {
/* TODO:
* With a more clever way of marking "don't copy to output N",
* This could easily be merged into a single loop with some
* dynamic realloc() instead of one count run and one malloc().
*/
std::fill_n(sources, MAX_CHANNELS, -1);
min_input_channels = 0;
min_output_channels = 0;
// A cowardly default, just passthrough stereo
const char *routes = param.GetBlockValue("routes", "0>0, 1>1");
while (true) {
routes = StripLeft(routes);
char *endptr;
const unsigned source = strtoul(routes, &endptr, 10);
endptr = StripLeft(endptr);
if (endptr == routes || *endptr != '>') {
error.Set(config_domain,
"Malformed 'routes' specification");
return false;
}
if (source >= MAX_CHANNELS) {
error.Format(config_domain,
"Invalid source channel number: %u",
source);
return false;
}
if (source >= min_input_channels)
min_input_channels = source + 1;
routes = StripLeft(endptr + 1);
unsigned dest = strtoul(routes, &endptr, 10);
endptr = StripLeft(endptr);
if (endptr == routes) {
error.Set(config_domain,
"Malformed 'routes' specification");
return false;
}
if (dest >= MAX_CHANNELS) {
error.Format(config_domain,
"Invalid destination channel number: %u",
dest);
return false;
}
if (dest >= min_output_channels)
min_output_channels = dest + 1;
sources[dest] = source;
routes = endptr;
if (*routes == 0)
break;
if (*routes != ',') {
error.Set(config_domain,
"Malformed 'routes' specification");
return false;
}
++routes;
}
return true;
}
static Filter *
route_filter_init(const config_param ¶m, Error &error)
{
RouteFilter *filter = new RouteFilter();
if (!filter->Configure(param, error)) {
delete filter;
return nullptr;
}
return filter;
}
AudioFormat
RouteFilter::Open(AudioFormat &audio_format, gcc_unused Error &error)
{
// Copy the input format for later reference
input_format = audio_format;
input_frame_size = input_format.GetFrameSize();
// Decide on an output format which has enough channels,
// and is otherwise identical
output_format = audio_format;
output_format.channels = min_output_channels;
// Precalculate this simple value, to speed up allocation later
output_frame_size = output_format.GetFrameSize();
return output_format;
}
void
RouteFilter::Close()
{
output_buffer.Clear();
}
ConstBuffer<void>
RouteFilter::FilterPCM(ConstBuffer<void> src, gcc_unused Error &error)
{
size_t number_of_frames = src.size / input_frame_size;
const size_t bytes_per_frame_per_channel = input_format.GetSampleSize();
// A moving pointer that always refers to channel 0 in the input, at the currently handled frame
const uint8_t *base_source = (const uint8_t *)src.data;
// Grow our reusable buffer, if needed, and set the moving pointer
const size_t result_size = number_of_frames * output_frame_size;
void *const result = output_buffer.Get(result_size);
// A moving pointer that always refers to the currently filled channel of the currently handled frame, in the output
uint8_t *chan_destination = (uint8_t *)result;
// Perform our copy operations, with N input channels and M output channels
for (unsigned int s=0; s<number_of_frames; ++s) {
// Need to perform one copy per output channel
for (unsigned int c=0; c<min_output_channels; ++c) {
if (sources[c] == -1 ||
(unsigned)sources[c] >= input_format.channels) {
// No source for this destination output,
// give it zeroes as input
memset(chan_destination,
0x00,
bytes_per_frame_per_channel);
} else {
// Get the data from channel sources[c]
// and copy it to the output
const uint8_t *data = base_source +
(sources[c] * bytes_per_frame_per_channel);
memcpy(chan_destination,
data,
bytes_per_frame_per_channel);
}
// Move on to the next output channel
chan_destination += bytes_per_frame_per_channel;
}
// Go on to the next N input samples
base_source += input_frame_size;
}
// Here it is, ladies and gentlemen! Rerouted data!
return { result, result_size };
}
const struct filter_plugin route_filter_plugin = {
"route",
route_filter_init,
};
