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Diffstat (limited to '')
-rw-r--r-- | src/filter/RouteFilterPlugin.cxx | 329 |
1 files changed, 329 insertions, 0 deletions
diff --git a/src/filter/RouteFilterPlugin.cxx b/src/filter/RouteFilterPlugin.cxx new file mode 100644 index 000000000..559578938 --- /dev/null +++ b/src/filter/RouteFilterPlugin.cxx @@ -0,0 +1,329 @@ +/* + * Copyright (C) 2003-2013 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 "conf.h" +#include "ConfigQuark.hxx" +#include "audio_format.h" +#include "audio_check.h" +#include "FilterPlugin.hxx" +#include "FilterInternal.hxx" +#include "FilterRegistry.hxx" +#include "pcm_buffer.h" + +#include <assert.h> +#include <string.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 char 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 char 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" + */ + signed char* sources; + + /** + * The actual input format of our signal, once opened + */ + struct audio_format input_format; + + /** + * The decided upon output format, once opened + */ + struct audio_format 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. + */ + struct pcm_buffer output_buffer; + +public: + RouteFilter():sources(nullptr) {} + ~RouteFilter() { + g_free(sources); + } + + /** + * 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 *param, GError **error_r); + + virtual const audio_format *Open(audio_format &af, GError **error_r); + virtual void Close(); + virtual const void *FilterPCM(const void *src, size_t src_size, + size_t *dest_size_r, GError **error_r); +}; + +bool +RouteFilter::Configure(const config_param *param, GError **error_r) { + + /* 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 g_realloc() instead of one count run and one g_malloc(). + */ + + gchar **tokens; + int number_of_copies; + + // A cowardly default, just passthrough stereo + const char *routes = + config_get_block_string(param, "routes", "0>0, 1>1"); + + min_input_channels = 0; + min_output_channels = 0; + + tokens = g_strsplit(routes, ",", 255); + number_of_copies = g_strv_length(tokens); + + // Start by figuring out a few basic things about the routing set + for (int c=0; c<number_of_copies; ++c) { + + // String and int representations of the source/destination + gchar **sd; + int source, dest; + + // Squeeze whitespace + g_strstrip(tokens[c]); + + // Split the a>b string into source and destination + sd = g_strsplit(tokens[c], ">", 2); + if (g_strv_length(sd) != 2) { + g_set_error(error_r, config_quark(), 1, + "Invalid copy around %d in routes spec: %s", + param->line, tokens[c]); + g_strfreev(sd); + g_strfreev(tokens); + return false; + } + + source = strtol(sd[0], NULL, 10); + dest = strtol(sd[1], NULL, 10); + + // Keep track of the highest channel numbers seen + // as either in- or outputs + if (source >= min_input_channels) + min_input_channels = source + 1; + if (dest >= min_output_channels) + min_output_channels = dest + 1; + + g_strfreev(sd); + } + + if (!audio_valid_channel_count(min_output_channels)) { + g_strfreev(tokens); + g_set_error(error_r, audio_format_quark(), 0, + "Invalid number of output channels requested: %d", + min_output_channels); + return false; + } + + // Allocate a map of "copy nothing to me" + sources = (signed char *) + g_malloc(min_output_channels * sizeof(signed char)); + + for (int i=0; i<min_output_channels; ++i) + sources[i] = -1; + + // Run through the spec again, and save the + // actual mapping output <- input + for (int c=0; c<number_of_copies; ++c) { + + // String and int representations of the source/destination + gchar **sd; + int source, dest; + + // Split the a>b string into source and destination + sd = g_strsplit(tokens[c], ">", 2); + if (g_strv_length(sd) != 2) { + g_set_error(error_r, config_quark(), 1, + "Invalid copy around %d in routes spec: %s", + param->line, tokens[c]); + g_strfreev(sd); + g_strfreev(tokens); + return false; + } + + source = strtol(sd[0], NULL, 10); + dest = strtol(sd[1], NULL, 10); + + sources[dest] = source; + + g_strfreev(sd); + } + + g_strfreev(tokens); + + return true; +} + +static Filter * +route_filter_init(const config_param *param, GError **error_r) +{ + RouteFilter *filter = new RouteFilter(); + if (!filter->Configure(param, error_r)) { + delete filter; + return nullptr; + } + + return filter; +} + +const struct audio_format * +RouteFilter::Open(audio_format &audio_format, gcc_unused GError **error_r) +{ + // Copy the input format for later reference + input_format = audio_format; + input_frame_size = audio_format_frame_size(&input_format); + + // 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 = audio_format_frame_size(&output_format); + + // This buffer grows as needed + pcm_buffer_init(&output_buffer); + + return &output_format; +} + +void +RouteFilter::Close() +{ + pcm_buffer_deinit(&output_buffer); +} + +const void * +RouteFilter::FilterPCM(const void *src, size_t src_size, + size_t *dest_size_r, gcc_unused GError **error_r) +{ + size_t number_of_frames = src_size / input_frame_size; + + size_t bytes_per_frame_per_channel = + audio_format_sample_size(&input_format); + + // 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; + + // A moving pointer that always refers to the currently filled channel of the currently handled frame, in the output + uint8_t *chan_destination; + + // Grow our reusable buffer, if needed, and set the moving pointer + *dest_size_r = number_of_frames * output_frame_size; + chan_destination = (uint8_t *) + pcm_buffer_get(&output_buffer, *dest_size_r); + + + // 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 (void *) output_buffer.buffer; +} + +const struct filter_plugin route_filter_plugin = { + "route", + route_filter_init, +}; |