mirror of
https://github.com/cookiengineer/audacity
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84 lines
2.5 KiB
C++
84 lines
2.5 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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*/
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#include "assert.h"
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#include "stdio.h"
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#include "string.h"
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#include "snd.h"
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#include "audioreader.h"
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#include "audiofilereader.h"
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double Audio_file_reader::get_sample_rate()
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{
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return snd.format.srate;
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}
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long Audio_file_reader::get_frames()
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{
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return (snd.u.file.end_offset - snd.u.file.byte_offset) /
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snd_bytes_per_frame(&snd);
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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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char *input_data = (char *) alloca(bytes_per_frame * samples_per_frame);
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assert(input_data != NULL) ;
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// read into the end of data
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long frames_read = snd_read(&snd, input_data, n);
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// now convert and move to beginning of data
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snd_node float_sound;
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float_sound.format = snd.format;
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float_sound.format.channels = 1; // make sure we convert to mono
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float_sound.format.mode = SND_MODE_FLOAT; // and convert to float
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float_sound.format.bits = 32;
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// note: snd_convert takes a frame count; divide samples by channels
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int converted = snd_convert(&float_sound, data, &snd, input_data, n);
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if (frames_read == n) assert(converted == n);
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return frames_read;
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}
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bool Audio_file_reader::open(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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snd.device = SND_DEVICE_FILE;
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snd.write_flag = SND_READ;
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strcpy(snd.u.file.filename, filename);
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long flags;
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int infile = snd_open(&snd, &flags);
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if (infile == SND_SUCCESS) {
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bytes_per_frame = snd_bytes_per_frame(&snd);
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calculate_parameters(sa, verbose);
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return true;
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}
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return false;
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}
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void Audio_file_reader::close()
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{
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snd_close(&snd);
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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", snd.u.file.filename);
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double sample_rate = snd.format.srate;
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printf(" sample rate = %g\n", sample_rate);
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printf(" channels = %d\n", snd.format.channels);
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/*=============================================================*/
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long frames =(snd.u.file.end_offset - snd.u.file.byte_offset) /
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snd_bytes_per_frame(&snd);
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printf(" total frames number is = %d\n", frames);
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printf(" bits per sample is %d\n", snd.format.bits);
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printf(" audio duration = %g seconds\n", (frames) / sample_rate);
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/*=============================================================*/
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}
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