cog/Plugins/MAD/MADDecoder.m

643 lines
16 KiB
Objective-C

//
// MADFile.m
// Cog
//
// Created by Vincent Spader on 6/17/06.
// Copyright 2006 Vincent Spader. All rights reserved.
//
#import "MADDecoder.h"
@implementation MADDecoder
#define LAME_HEADER_SIZE ((8 * 5) + 4 + 4 + 8 + 32 + 16 + 16 + 4 + 4 + 8 + 12 + 12 + 8 + 8 + 2 + 3 + 11 + 32 + 32 + 32)
// From vbrheadersdk:
// ========================================
// A Xing header may be present in the ancillary
// data field of the first frame of an mp3 bitstream
// The Xing header (optionally) contains
// frames total number of audio frames in the bitstream
// bytes total number of bytes in the bitstream
// toc table of contents
// toc (table of contents) gives seek points
// for random access
// the ith entry determines the seek point for
// i-percent duration
// seek point in bytes = (toc[i]/256.0) * total_bitstream_bytes
// e.g. half duration seek point = (toc[50]/256.0) * total_bitstream_bytes
#define FRAMES_FLAG 0x0001
#define BYTES_FLAG 0x0002
#define TOC_FLAG 0x0004
#define VBR_SCALE_FLAG 0x0008
//Scan file quickly
- (BOOL)scanFile
{
struct mad_stream stream;
struct mad_frame frame;
int framesDecoded = 0;
int bytesToRead, bytesRemaining;
int samplesPerMPEGFrame = 0;
int id3_length = 0;
mad_stream_init (&stream);
mad_frame_init (&frame);
[_source seek:0 whence:SEEK_END];
_fileSize = [_source tell];
[_source seek:0 whence:SEEK_SET];
for (;;) {
if(NULL == stream.buffer || MAD_ERROR_BUFLEN == stream.error) {
if(stream.next_frame) {
bytesRemaining = stream.bufend - stream.next_frame;
memmove(_inputBuffer, stream.next_frame, bytesRemaining);
bytesToRead = INPUT_BUFFER_SIZE - bytesRemaining;
}
else {
bytesToRead = INPUT_BUFFER_SIZE,
bytesRemaining = 0;
}
// Read raw bytes from the MP3 file
int bytesRead = [_source read:_inputBuffer + bytesRemaining amount: bytesToRead];
if (bytesRead == 0)
{
memset(_inputBuffer + bytesRemaining + bytesRead, 0, MAD_BUFFER_GUARD);
bytesRead += MAD_BUFFER_GUARD;
inputEOF = YES;
}
mad_stream_buffer(&stream, _inputBuffer, bytesRead + bytesRemaining);
stream.error = MAD_ERROR_NONE;
}
if (mad_frame_decode(&frame, &stream) == -1)
{
if (MAD_RECOVERABLE(stream.error))
{
// Prevent ID3 tags from reporting recoverable frame errors
const uint8_t *buffer = stream.this_frame;
unsigned buflen = stream.bufend - stream.this_frame;
if(10 <= buflen && 0x49 == buffer[0] && 0x44 == buffer[1] && 0x33 == buffer[2]) {
id3_length = (((buffer[6] & 0x7F) << (3 * 7)) | ((buffer[7] & 0x7F) << (2 * 7)) |
((buffer[8] & 0x7F) << (1 * 7)) | ((buffer[9] & 0x7F) << (0 * 7)));
// Add 10 bytes for ID3 header
id3_length += 10;
mad_stream_skip(&stream, id3_length);
}
continue;
}
else if (stream.error == MAD_ERROR_BUFLEN && inputEOF)
{
break;
}
else if (stream.error == MAD_ERROR_BUFLEN)
{
continue;
}
else
{
//NSLog(@"Unrecoverable error: %s", mad_stream_errorstr(&stream));
break;
}
}
framesDecoded++;
if (framesDecoded == 1)
{
sampleRate = frame.header.samplerate;
channels = MAD_NCHANNELS(&frame.header);
if(MAD_FLAG_LSF_EXT & frame.header.flags || MAD_FLAG_MPEG_2_5_EXT & frame.header.flags) {
switch(frame.header.layer) {
case MAD_LAYER_I: samplesPerMPEGFrame = 384; break;
case MAD_LAYER_II: samplesPerMPEGFrame = 1152; break;
case MAD_LAYER_III: samplesPerMPEGFrame = 576; break;
}
}
else {
switch(frame.header.layer) {
case MAD_LAYER_I: samplesPerMPEGFrame = 384; break;
case MAD_LAYER_II: samplesPerMPEGFrame = 1152; break;
case MAD_LAYER_III: samplesPerMPEGFrame = 1152; break;
}
}
unsigned ancillaryBitsRemaining = stream.anc_bitlen;
if(32 > ancillaryBitsRemaining)
continue;
uint32_t magic = mad_bit_read(&stream.anc_ptr, 32);
ancillaryBitsRemaining -= 32;
if('Xing' == magic || 'Info' == magic) {
unsigned i;
uint32_t flags = 0, frames = 0, bytes = 0, vbrScale = 0;
if(32 > ancillaryBitsRemaining)
continue;
flags = mad_bit_read(&stream.anc_ptr, 32);
ancillaryBitsRemaining -= 32;
// 4 byte value containing total frames
if(FRAMES_FLAG & flags) {
if(32 > ancillaryBitsRemaining)
continue;
frames = mad_bit_read(&stream.anc_ptr, 32);
ancillaryBitsRemaining -= 32;
// Determine number of samples, discounting encoder delay and padding
// Our concept of a frame is the same as CoreAudio's- one sample across all channels
totalFrames = frames * samplesPerMPEGFrame;
//NSLog(@"TOTAL READ FROM XING");
}
// 4 byte value containing total bytes
if(BYTES_FLAG & flags) {
if(32 > ancillaryBitsRemaining)
continue;
bytes = mad_bit_read(&stream.anc_ptr, 32);
ancillaryBitsRemaining -= 32;
}
// 100 bytes containing TOC information
if(TOC_FLAG & flags) {
if(8 * 100 > ancillaryBitsRemaining)
continue;
for(i = 0; i < 100; ++i)
/*_xingTOC[i] = */ mad_bit_read(&stream.anc_ptr, 8);
ancillaryBitsRemaining -= (8* 100);
}
// 4 byte value indicating encoded vbr scale
if(VBR_SCALE_FLAG & flags) {
if(32 > ancillaryBitsRemaining)
continue;
vbrScale = mad_bit_read(&stream.anc_ptr, 32);
ancillaryBitsRemaining -= 32;
}
framesDecoded = frames;
_foundXingHeader = YES;
// Loook for the LAME header next
// http://gabriel.mp3-tech.org/mp3infotag.html
if(32 > ancillaryBitsRemaining)
continue;
magic = mad_bit_read(&stream.anc_ptr, 32);
ancillaryBitsRemaining -= 32;
if('LAME' == magic) {
if(LAME_HEADER_SIZE > ancillaryBitsRemaining)
continue;
/*unsigned char versionString [5 + 1];
memset(versionString, 0, 6);*/
for(i = 0; i < 5; ++i)
/*versionString[i] =*/ mad_bit_read(&stream.anc_ptr, 8);
/*uint8_t infoTagRevision =*/ mad_bit_read(&stream.anc_ptr, 4);
/*uint8_t vbrMethod =*/ mad_bit_read(&stream.anc_ptr, 4);
/*uint8_t lowpassFilterValue =*/ mad_bit_read(&stream.anc_ptr, 8);
/*float peakSignalAmplitude =*/ mad_bit_read(&stream.anc_ptr, 32);
/*uint16_t radioReplayGain =*/ mad_bit_read(&stream.anc_ptr, 16);
/*uint16_t audiophileReplayGain =*/ mad_bit_read(&stream.anc_ptr, 16);
/*uint8_t encodingFlags =*/ mad_bit_read(&stream.anc_ptr, 4);
/*uint8_t athType =*/ mad_bit_read(&stream.anc_ptr, 4);
/*uint8_t lameBitrate =*/ mad_bit_read(&stream.anc_ptr, 8);
_startPadding = mad_bit_read(&stream.anc_ptr, 12);
_endPadding = mad_bit_read(&stream.anc_ptr, 12);
_startPadding += 528 + 1; //MDCT/filterbank delay
totalFrames += 528 + 1;
/*uint8_t misc =*/ mad_bit_read(&stream.anc_ptr, 8);
/*uint8_t mp3Gain =*/ mad_bit_read(&stream.anc_ptr, 8);
/*uint8_t unused =*/mad_bit_read(&stream.anc_ptr, 2);
/*uint8_t surroundInfo =*/ mad_bit_read(&stream.anc_ptr, 3);
/*uint16_t presetInfo =*/ mad_bit_read(&stream.anc_ptr, 11);
/*uint32_t musicGain =*/ mad_bit_read(&stream.anc_ptr, 32);
/*uint32_t musicCRC =*/ mad_bit_read(&stream.anc_ptr, 32);
/*uint32_t tagCRC =*/ mad_bit_read(&stream.anc_ptr, 32);
ancillaryBitsRemaining -= LAME_HEADER_SIZE;
_foundLAMEHeader = YES;
break;
}
}
}
else
{
totalFrames = (double)frame.header.samplerate * ((_fileSize - id3_length) / (frame.header.bitrate / 8.0));
//NSLog(@"Guestimating total samples");
break;
}
}
bitrate = ((_fileSize - id3_length)/128) * (sampleRate/totalFrames);
mad_frame_finish (&frame);
mad_stream_finish (&stream);
bitsPerSample = 16;
bytesPerFrame = (bitsPerSample/8) * channels;
[_source seek:0 whence:SEEK_SET];
inputEOF = NO;
NSLog(@"Mad properties: %@", [self properties]);
return YES;
}
- (BOOL)open:(id<CogSource>)source
{
[source retain];
[_source release];
_source = source;
/* First the structures used by libmad must be initialized. */
mad_stream_init(&_stream);
mad_frame_init(&_frame);
mad_synth_init(&_synth);
_firstFrame = YES;
//NSLog(@"OPEN: %i", _firstFrame);
inputEOF = NO;
if (![_source seekable])
{
//Decode the first frame to get the channels, samplerate, etc.
int r;
do {
r = [self decodeMPEGFrame];
NSLog(@"Decoding frame: %i", r);
} while (r == 0);
return (r == -1 ? NO : YES);
}
return [self scanFile];
}
/**
* Scale PCM data
*/
static inline signed int scale (mad_fixed_t sample)
{
BOOL hard_limit = YES;
double scale = 1.0;
/* hard-limit (clipping-prevention) */
if (hard_limit)
{
/* convert to double before computation, to avoid mad_fixed_t wrapping */
double x = mad_f_todouble(sample) * scale;
static const double k = 0.5; // -6dBFS
if (x > k)
{
x = tanh((x - k) / (1-k)) * (1-k) + k;
}
else if(x < -k)
{
x = tanh((x + k) / (1-k)) * (1-k) - k;
}
sample = x * (MAD_F_ONE);
}
else
sample *= scale;
int n_bits_to_loose = MAD_F_FRACBITS + 1 - 16;
/* round */
/* add half of the bits_to_loose range to round */
sample += (1L << (n_bits_to_loose - 1));
/* clip */
/* make sure we are between -1 and 1 */
if (sample >= MAD_F_ONE)
{
sample = MAD_F_ONE - 1;
}
else if (sample < -MAD_F_ONE)
{
sample = -MAD_F_ONE;
}
/* quantize */
/*
* Turn our mad_fixed_t into an integer.
* Shift all but 16-bits of the fractional part
* off the right hand side and shift an extra place
* to get the sign bit.
*/
sample >>= n_bits_to_loose;
return sample;
}
- (void)writeOutput
{
unsigned int startingSample = 0;
unsigned int sampleCount = _synth.pcm.length;
//NSLog(@"Position: %li/%li", _framesDecoded, totalFrames);
//NSLog(@"<%i, %i>", _startPadding, _endPadding);
//NSLog(@"Counts: %i, %i", startingSample, sampleCount);
if (_foundLAMEHeader) {
if (_framesDecoded < _startPadding) {
//NSLog(@"Skipping start.");
startingSample = _startPadding - _framesDecoded;
}
if (_framesDecoded > totalFrames - _endPadding + startingSample) {
//NSLog(@"End of file. Not writing.");
return;
}
if (_framesDecoded + (sampleCount - startingSample) > totalFrames - _endPadding) {
sampleCount = totalFrames - _endPadding - _framesDecoded + startingSample;
//NSLog(@"End of file. %li", totalFrames - _endPadding - _framesDecoded);
}
if (startingSample > sampleCount) {
_framesDecoded += _synth.pcm.length;
//NSLog(@"Skipping entire sample");
return;
}
}
//NSLog(@"Revised: %i, %i", startingSample, sampleCount);
_framesDecoded += _synth.pcm.length;
_outputFrames = (sampleCount - startingSample);
if (_outputBuffer)
free(_outputBuffer);
_outputBuffer = (unsigned char *) malloc (_outputFrames * bytesPerFrame * sizeof (char));
unsigned int i, j;
unsigned int stride = channels * 2;
for (j = 0; j < channels; j++)
{
/* output sample(s) in 16-bit signed little-endian PCM */
mad_fixed_t const *channel = _synth.pcm.samples[j];
unsigned char *outputPtr = _outputBuffer + (j * 2);
for (i = startingSample; i < sampleCount; i++)
{
signed short sample = scale(channel[i]);
outputPtr[0] = sample>>8;
outputPtr[1] = sample & 0xff;
outputPtr += stride;
}
}
}
- (int)decodeMPEGFrame
{
if (_stream.buffer == NULL || _stream.error == MAD_ERROR_BUFLEN)
{
int inputToRead;
int inputRemaining;
if (_stream.next_frame != NULL)
{
inputRemaining = _stream.bufend - _stream.next_frame;
memmove(_inputBuffer, _stream.next_frame, inputRemaining);
inputToRead = INPUT_BUFFER_SIZE - inputRemaining;
}
else
{
inputToRead = INPUT_BUFFER_SIZE;
inputRemaining = 0;
}
int inputRead = [_source read:_inputBuffer + inputRemaining amount:INPUT_BUFFER_SIZE - inputRemaining];
if (inputRead == 0)
{
memset(_inputBuffer + inputRemaining + inputRead, 0, MAD_BUFFER_GUARD);
inputRead += MAD_BUFFER_GUARD;
inputEOF = YES;
}
mad_stream_buffer(&_stream, _inputBuffer, inputRead + inputRemaining);
_stream.error = MAD_ERROR_NONE;
//NSLog(@"Read stream.");
}
if (mad_frame_decode(&_frame, &_stream) == -1) {
if (MAD_RECOVERABLE (_stream.error))
{
const uint8_t *buffer = _stream.this_frame;
unsigned buflen = _stream.bufend - _stream.this_frame;
uint32_t id3_length = 0;
//No longer need ID3Tag framework
if(10 <= buflen && 0x49 == buffer[0] && 0x44 == buffer[1] && 0x33 == buffer[2]) {
id3_length = (((buffer[6] & 0x7F) << (3 * 7)) | ((buffer[7] & 0x7F) << (2 * 7)) |
((buffer[8] & 0x7F) << (1 * 7)) | ((buffer[9] & 0x7F) << (0 * 7)));
// Add 10 bytes for ID3 header
id3_length += 10;
mad_stream_skip(&_stream, id3_length);
}
NSLog(@"recoverable error");
return 0;
}
else if (MAD_ERROR_BUFLEN == _stream.error && inputEOF)
{
NSLog(@"EOF");
return -1;
}
else if (MAD_ERROR_BUFLEN == _stream.error)
{
NSLog(@"Bufferlen");
return 0;
}
else
{
//NSLog(@"Unrecoverable stream error: %s", mad_stream_errorstr(&_stream));
return -1;
}
}
//NSLog(@"Decoded buffer.");
mad_synth_frame (&_synth, &_frame);
//NSLog(@"first frame: %i", _firstFrame);
if (_firstFrame)
{
_firstFrame = NO;
if (![_source seekable]) {
sampleRate = _frame.header.samplerate;
channels = MAD_NCHANNELS(&_frame.header);
bitsPerSample = 16;
bytesPerFrame = (bitsPerSample/8) * channels;
[self willChangeValueForKey:@"properties"];
[self didChangeValueForKey:@"properties"];
}
//NSLog(@"FIRST FRAME!!! %i %i", _foundXingHeader, _foundLAMEHeader);
if (_foundXingHeader) {
//NSLog(@"Skipping xing header.");
return 0;
}
}
return 1;
}
- (int)readAudio:(void *)buffer frames:(UInt32)frames
{
int framesRead = 0;
for (;;)
{
int framesRemaining = frames - framesRead;
int framesToCopy = (_outputFrames > framesRemaining ? framesRemaining : _outputFrames);
if (framesToCopy) {
memcpy(buffer + (framesRead * bytesPerFrame), _outputBuffer, framesToCopy*bytesPerFrame);
framesRead += framesToCopy;
if (framesToCopy != _outputFrames) {
memmove(_outputBuffer, _outputBuffer + (framesToCopy*bytesPerFrame), (_outputFrames - framesToCopy)*bytesPerFrame);
}
_outputFrames -= framesToCopy;
}
if (framesRead == frames)
break;
int r = [self decodeMPEGFrame];
NSLog(@"Decoding frame: %i", r);
if (r == 0) //Recoverable error.
continue;
else if (r == -1) //Unrecoverable error
break;
[self writeOutput];
//NSLog(@"Wrote output");
}
//NSLog(@"Read: %i/%i", bytesRead, size);
return framesRead;
}
- (void)close
{
if (_source)
{
[_source close];
[_source release];
_source = nil;
}
if (_outputBuffer)
{
free(_outputBuffer);
_outputBuffer = NULL;
}
mad_synth_finish(&_synth);
mad_frame_finish(&_frame);
mad_stream_finish(&_stream);
}
- (long)seek:(long)frame
{
if (frame > totalFrames)
frame = totalFrames;
unsigned long new_position = ((double)frame / totalFrames) * _fileSize;
[_source seek:new_position whence:SEEK_SET];
mad_stream_buffer(&_stream, NULL, 0);
//Gapless busted after seek. Mp3 just doesn't have sample-accurate seeking. Maybe xing toc?
_framesDecoded = frame;
return frame;
}
- (NSDictionary *)properties
{
return [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithInt:channels],@"channels",
[NSNumber numberWithInt:bitsPerSample],@"bitsPerSample",
[NSNumber numberWithFloat:sampleRate],@"sampleRate",
[NSNumber numberWithInt:bitrate],@"bitrate",
[NSNumber numberWithLong:totalFrames],@"totalFrames",
[NSNumber numberWithBool:[_source seekable]], @"seekable",
@"big", @"endian",
nil];
}
+ (NSArray *)fileTypes
{
return [NSArray arrayWithObjects:@"mp3",nil];
}
+ (NSArray *)mimeTypes
{
return [NSArray arrayWithObjects:@"audio/mpeg", @"audio/x-mp3", nil];
}
@end