mirror of
https://github.com/cookiengineer/audacity
synced 2025-10-31 14:13:50 +01:00
103 lines
2.8 KiB
C++
103 lines
2.8 KiB
C++
/* audiofilereader.cpp -- implements a class to read samples
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*
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* 14-Jun-08 RBD
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* 16-Jun-08 RBD revised to use libsndfile
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*/
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#include "assert.h"
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#include "stdlib.h"
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#include "stdio.h"
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#include "string.h"
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#include "sndfile.h"
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#include "audioreader.h"
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#include "audiofilereader.h"
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#ifdef WIN32
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#include <malloc.h>
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#include <windows.h>
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#define bzero(addr, siz) memset(addr, 0, siz)
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#define alloca _alloca
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#endif
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double Audio_file_reader::get_sample_rate()
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{
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return sf_info.samplerate;
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}
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long Audio_file_reader::get_frames()
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{
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return total_frames;
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}
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long Audio_file_reader::read(float *data, long n)
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{
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// note that "samples_per_frame" is really "frames_per_window" in this
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// context, so we're computing bytes per window
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float *input_data = (float *) alloca(bytes_per_frame * samples_per_frame);
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assert(input_data != NULL) ;
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long frames_read = (long) sf_readf_float(sf, input_data, n);
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long chans = sf_info.channels;
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// now convert to mono and move to data
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for (int frame = 0; frame < frames_read; frame++) {
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float sum = 0;
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for (int chan = 0; chan < sf_info.channels; chan++) {
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// sum over channels within a frame
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sum += input_data[frame * chans + chan];
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}
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// write the frame sum to result array
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data[frame] = sum;
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}
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return frames_read;
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}
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bool Audio_file_reader::open(const char *filename, Scorealign &sa, bool verbose)
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{
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bytes_per_frame = 0; // initialize now in case an error occurs
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name[0] = 0;
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bzero(&sf_info, sizeof(sf_info));
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sf = sf_open(filename, SFM_READ, &sf_info);
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if (!sf) {
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#ifdef WIN32
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/* windows-specific code to report error opening file */
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char *msg;
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DWORD code = GetLastError();
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DWORD code2 = FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER |
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FORMAT_MESSAGE_FROM_SYSTEM,
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0, code, 0, (LPSTR) &msg, 0, 0);
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printf("Error string: %s\n", msg);
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LocalFree(msg);
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#endif
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return false;
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}
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strncpy(name, filename, MAX_NAME_LEN);
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name[MAX_NAME_LEN] = 0; // just in case
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total_frames = (long) sf_seek(sf, 0, SEEK_END);
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sf_seek(sf, 0, SEEK_SET);
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// we're going to read floats, but they might be multi-channel...
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bytes_per_frame = sf_info.channels * sizeof(float);
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calculate_parameters(sa, verbose);
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return true;
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}
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void Audio_file_reader::close()
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{
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sf_close(sf);
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}
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void Audio_file_reader::print_info()
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{
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printf(" file name = %s\n", name);
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double sample_rate = sf_info.samplerate;
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printf(" sample rate = %g\n", sample_rate);
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printf(" channels = %d\n", sf_info.channels);
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/*=============================================================*/
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printf(" total frames number is = %ld\n", total_frames);
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printf(" audio duration = %g seconds\n", total_frames / sample_rate);
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/*=============================================================*/
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}
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