// Calculate the number of samples per packet
size_t MastCodec_MPA::frames_per_packet_internal( size_t max_bytes )
{
int frames_per_packet = max_bytes/twolame_get_framelength( this->twolame );
MAST_DEBUG("MPEG Audio Frames per Packet: %d", frames_per_packet );
return frames_per_packet*TWOLAME_SAMPLES_PER_FRAME;
}
int main(int argc, char **argv)
{
twolame_options *encopts = NULL;
audioin_t *inputfile = NULL;
FILE *outputfile = NULL;
short int *pcmaudio = NULL;
unsigned int frame_count = 0;
unsigned int total_frames = 0;
unsigned int frame_len = 0;
unsigned int total_bytes = 0;
unsigned char *mp2buffer = NULL;
int samples_read = 0;
int mp2fill_size = 0;
int audioReadSize = 0;
// Allocate memory for the PCM audio data
if ((pcmaudio = (short int *) calloc(AUDIO_BUF_SIZE, sizeof(short int))) == NULL) {
fprintf(stderr, "Error: pcmaudio memory allocation failed\n");
exit(ERR_MEM_ALLOC);
}
// Allocate memory for the encoded MP2 audio data
if ((mp2buffer = (unsigned char *) calloc(MP2_BUF_SIZE, sizeof(unsigned char))) == NULL) {
fprintf(stderr, "Error: mp2buffer memory allocation failed\n");
exit(ERR_MEM_ALLOC);
}
// Initialise Encoder Options Structure
encopts = twolame_init();
if (encopts == NULL) {
fprintf(stderr, "Error: initializing libtwolame encoder failed.\n");
exit(ERR_MEM_ALLOC);
}
// Get options and parameters from the command line
parse_args(argc, argv, encopts);
// Display the filenames
print_filenames(twolame_get_verbosity(encopts));
// Open the input file
if (use_raw) {
// use raw input handler
inputfile = open_audioin_raw(inputfilename, &sfinfo, sample_size);
} else {
// use libsndfile
inputfile = open_audioin_sndfile(inputfilename, &sfinfo);
}
// Display input information
if (twolame_get_verbosity(encopts) > 1) {
inputfile->print_info(inputfile);
}
// Use information from input file to configure libtwolame
twolame_set_num_channels(encopts, sfinfo.channels);
twolame_set_in_samplerate(encopts, sfinfo.samplerate);
// Open the output file
outputfile = open_output_file(outputfilename);
// initialise twolame with this set of options
if (twolame_init_params(encopts) != 0) {
fprintf(stderr, "Error: configuring libtwolame encoder failed.\n");
exit(ERR_INVALID_PARAM);
}
// display encoder settings
twolame_print_config(encopts);
// Only encode a single frame of mpeg audio ?
if (single_frame_mode)
audioReadSize = TWOLAME_SAMPLES_PER_FRAME;
else
audioReadSize = AUDIO_BUF_SIZE;
// Calculate the size and number of frames we are going to encode
frame_len = twolame_get_framelength(encopts);
if (sfinfo.frames)
total_frames = sfinfo.frames / TWOLAME_SAMPLES_PER_FRAME;
// Now do the reading/encoding/writing
while ((samples_read = inputfile->read(inputfile, pcmaudio, audioReadSize)) > 0) {
int bytes_out = 0;
// Force byte swapping if requested
if (byteswap) {
int i;
for (i = 0; i < samples_read; i++) {
short tmp = pcmaudio[i];
char *src = (char *) &tmp;
char *dst = (char *) &pcmaudio[i];
dst[0] = src[1];
dst[1] = src[0];
}
}
// Calculate the number of samples we have (per channel)
samples_read /= sfinfo.channels;
// Do swapping of left and right channels if requested
if (channelswap && sfinfo.channels == 2) {
int i;
for (i = 0; i < samples_read; i++) {
short tmp = pcmaudio[(2 * i)];
pcmaudio[(2 * i)] = pcmaudio[(2 * i) + 1];
pcmaudio[(2 * i) + 1] = tmp;
}
}
// Encode the audio to MP2
mp2fill_size =
twolame_encode_buffer_interleaved(encopts, pcmaudio, samples_read, mp2buffer,
MP2_BUF_SIZE);
// Stop if we don't have any bytes (probably don't have enough audio for a full frame of
// mpeg audio)
if (mp2fill_size == 0)
break;
if (mp2fill_size < 0) {
fprintf(stderr, "error while encoding audio: %d\n", mp2fill_size);
exit(ERR_ENCODING);
}
// Check that a whole number of frame was written
// if (mp2fill_size % frame_len != 0) {
// fprintf(stderr,"error while encoding audio: non-whole number of frames written\n");
// exit(ERR_ENCODING);
// }
// Write the encoded audio out
bytes_out = fwrite(mp2buffer, sizeof(unsigned char), mp2fill_size, outputfile);
if (bytes_out != mp2fill_size) {
perror("error while writing to output file");
exit(ERR_WRITING_OUTPUT);
}
total_bytes += bytes_out;
// Only single frame ?
if (single_frame_mode)
break;
// Display Progress
frame_count += (mp2fill_size / frame_len);
if (twolame_get_verbosity(encopts) > 0) {
fprintf(stderr, "\rEncoding frame: %i", frame_count);
if (total_frames) {
fprintf(stderr, "/%i (%i%%)", total_frames, (frame_count * 100) / total_frames);
}
fflush(stderr);
}
}
// Was there an error reading the audio?
if (inputfile->error_str(inputfile)) {
fprintf(stderr, "Error reading from input file: %s\n", inputfile->error_str(inputfile));
}
//
// flush any remaining audio. (don't send any new audio data) There
// should only ever be a max of 1 frame on a flush. There may be zero
// frames if the audio data was an exact multiple of 1152
//
mp2fill_size = twolame_encode_flush(encopts, mp2buffer, MP2_BUF_SIZE);
if (mp2fill_size > 0) {
int bytes_out = fwrite(mp2buffer, sizeof(unsigned char), mp2fill_size, outputfile);
frame_count++;
if (bytes_out <= 0) {
perror("error while writing to output file");
exit(ERR_WRITING_OUTPUT);
}
total_bytes += bytes_out;
}
if (twolame_get_verbosity(encopts) > 1) {
char *filesize = format_filesize_string(total_bytes);
fprintf(stderr, "\nEncoding Finished.\n");
fprintf(stderr, "Total bytes written: %s.\n", filesize);
free(filesize);
}
// Close input and output streams
inputfile->close(inputfile);
fclose(outputfile);
// Close the libtwolame encoder
twolame_close(&encopts);
// Free up memory
free(pcmaudio);
free(mp2buffer);
return (ERR_NO_ERROR);
}
