redquark-amiberry-rb/src/od-pandora/mp3decoder.cpp

#include "sysconfig.h"
#include "sysdeps.h"

#include "zfile.h"
#include "mp3decoder.h"
#include "cda_play.h"
#include <mpg123.h>


#define MP3_BLOCK_SIZE 522
#define RAW_BLOCK_SIZE 32768

static int mp3_bitrates[] = {
  0,  32,  64,  96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448, -1,
  0,  32,  48,  56,  64,  80,  96, 112, 128, 160, 192, 224, 256, 320, 384, -1,
  0,  32,  40,  48,  56,  64,  80,  96, 112, 128, 160, 192, 224, 256, 320, -1,
  0,  32,  48,  56,  64,  80,  96, 112, 128, 144, 160, 176, 192, 224, 256, -1,
  0,   8,  16,  24,  32,  40,  48,  56,  64,  80,  96, 112, 128, 144, 160, -1
};
static int mp3_frequencies[] = {
	44100, 48000, 32000, 0,
	22050, 24000, 16000, 0,
	11025, 12000,  8000, 0
};
static int mp3_samplesperframe[] = {
	 384,  384,  384,
	1152, 1152, 1152,
	1152,  576,  576
};

mp3decoder::~mp3decoder() 
{
}

mp3decoder::mp3decoder() 
{
}

uae_u8 *mp3decoder::get (struct zfile *zf, uae_u8 *outbuf, int maxsize) 
{
	int outoffset = 0;
	unsigned char mp3buf[MP3_BLOCK_SIZE];
  unsigned char rawbuf[RAW_BLOCK_SIZE];
  
	write_log(_T("MP3: decoding '%s'..\n"), zfile_getname(zf));

  if(mpg123_init() != MPG123_OK) {
    write_log("MP3: failed to init mpeg123\n");
    return NULL;
  }
  
  const char** decoders = mpg123_decoders();
  if(decoders == NULL || decoders[0] == NULL) {
    write_log("MP3: no mp3 decoder available\n");
    mpg123_exit();
    return NULL;
  }
  
  mpg123_handle *mh = mpg123_new(NULL, NULL); // Open default decoder
  if(mh == NULL) {
    write_log("MP3: failed to init default decoder\n");
    mpg123_exit();
    return NULL;
  }

  if(mpg123_open_feed(mh) == MPG123_OK) {
  	zfile_fseek(zf, 0, SEEK_SET);
  	for (; outoffset < maxsize; ) {
  		int count = zfile_fread(mp3buf, 1, MP3_BLOCK_SIZE, zf);
  		if (count != MP3_BLOCK_SIZE)
  			break;
  	  
  	  size_t decoded = 0;
  	  int ret = mpg123_decode(mh, mp3buf, MP3_BLOCK_SIZE, rawbuf, RAW_BLOCK_SIZE, &decoded);
      
      if(ret != MPG123_ERR && decoded != 0) {
        if(outoffset + decoded > maxsize)
          decoded = maxsize - outoffset;
        memcpy(outbuf + outoffset, rawbuf, decoded);
        outoffset += decoded;
      }
      
      while(ret != MPG123_ERR && ret != MPG123_NEED_MORE && outoffset < maxsize) {
        ret = mpg123_decode(mh, NULL, 0, rawbuf, RAW_BLOCK_SIZE, &decoded);
        if(ret != MPG123_ERR && decoded != 0) {
          if(outoffset + decoded > maxsize)
            decoded = maxsize - outoffset;
          memcpy(outbuf + outoffset, rawbuf, decoded);
          outoffset += decoded;
        }
      }
      
      if(ret == MPG123_ERR) {
        write_log("MP3: error while decoding\n");
        outbuf = NULL;
        break;
      }
    }

    mpg123_close(mh);
  }
    
  mpg123_delete(mh);
  mpg123_exit();
    
  return outbuf;
}

uae_u32 mp3decoder::getsize (struct zfile *zf) 
{
	uae_u32 size;
	int frames, sameframes;
	int firstframe;
	int oldbitrate;
	int timelen = -1;

	firstframe = -1;
	oldbitrate = -1;
	sameframes = -1;
	frames = 0;
	size = 0;
	uae_u8 id3[10];

	if (zfile_fread(id3, sizeof id3, 1, zf) != 1)
		return 0;
	if (id3[0] == 'I' && id3[1] == 'D' && id3[2] == '3' && id3[3] == 3 && id3[4] != 0xff && id3[6] < 0x80 && id3[7] < 0x80 && id3[8] < 0x80 && id3[9] < 0x80) {
		int unsync = id3[5] & 0x80;
		int exthead = id3[5] & 0x40;
		int len = (id3[9] << 0) | (id3[8] << 7) | (id3[7] << 14) | (id3[6] << 21);
		len &= 0x0fffffff;
		uae_u8 *tag = xmalloc (uae_u8, len + 1);
		if (zfile_fread (tag, len, 1, zf) != 1) {
			xfree (tag);
			return 0;
		}
		uae_u8 *p = tag;
		if (exthead) {
			int size = (p[4] << 21) | (p[5] << 14) | (p[6] << 7);
			size &= 0x0fffffff;
			p += size;
			len -= size;
		}
		while (len > 0) {
			int size = unsync ? (p[4] << 21) | (p[5] << 14) | (p[6] << 7) | (p[7] << 0) : (p[4] << 24) | (p[5] << 16) | (p[6] << 8) | (p[7] << 0);
			size &= 0x0fffffff;
			if (size > len)
				break;
			int compr = p[9] & 0x80;
			int enc = p[9] & 0x40;
			if (compr == 0 && enc == 0) {
				if (!memcmp (p, "TLEN", 4)) {
					uae_u8 *data = p + 10;
					data[size] = 0;
					if (data[0] ==  0)
						timelen = atol ((char*)(data + 1));
					else
						timelen = _tstol ((char*)(data + 1));
				}
			}
			size += 10;
			p += size;
			len -= size;
		}
		xfree (tag);
	} else {
		zfile_fseek(zf, -(int)sizeof id3, SEEK_CUR);
	}


	for (;;) {
		int ver, layer, bitrate, freq, padding, bitindex, iscrc;
		int samplerate, framelen, bitrateidx, channelmode;
		int isstereo;
		uae_u8 header[4];

		if (zfile_fread(header, sizeof header, 1, zf) != 1)
			return size;
		if (header[0] != 0xff || ((header[1] & (0x80 | 0x40 | 0x20)) != (0x80 | 0x40 | 0x20))) {
			zfile_fseek (zf, -3, SEEK_CUR);
			continue;
		}
		if (firstframe < 0)
			firstframe = zfile_ftell (zf);

		ver = (header[1] >> 3) & 3;
		if (ver == 1) {
			write_log (_T("MP3: ver==1?!\n"));
			return 0;
		}
		if (ver == 0)
			ver = 2;
		else if (ver == 2)
			ver = 1;
		else if (ver == 3)
			ver = 0;
		layer = 4 - ((header[1] >> 1) & 3);
		if (layer == 4) {
			write_log (_T("MP3: layer==4?!\n"));
			return 0;
		}
		iscrc = ((header[1] >> 0) & 1) ? 0 : 2;
		bitrateidx = (header[2] >> 4) & 15;
		freq = mp3_frequencies[(header[2] >> 2) & 3];
		if (!freq) {
			write_log (_T("MP3: reserved frequency?!\n"));
			return 0;
		}
		channelmode = (header[3] >> 6) & 3;
		isstereo = channelmode != 3;
		if (ver == 0) {
			bitindex = layer - 1;
		} else {
			if (layer == 1)
				bitindex = 3;
			else
				bitindex = 4;
		}
		bitrate = mp3_bitrates[bitindex * 16 + bitrateidx] * 1000;
		if (bitrate <= 0) {
			write_log (_T("MP3: reserved bitrate?!\n"));
			return 0;
		}
		padding = (header[2] >> 1) & 1;
		samplerate = mp3_samplesperframe[(layer - 1) * 3 + ver];
		framelen = ((samplerate / 8 * bitrate) / freq) + padding;
		if (framelen <= 4) {
			write_log (_T("MP3: too small frame size?!\n"));
			return 0;
		}
		zfile_fseek(zf, framelen - 4, SEEK_CUR);
		frames++;
		if (timelen > 0) {
			size = ((uae_u64)timelen * freq * 2 * (isstereo ? 2 : 1)) / 1000;
			break;
		}
		size += samplerate * 2 * (isstereo ? 2 : 1);
		if (bitrate != oldbitrate) {
			oldbitrate = bitrate;
			sameframes++;
		}
		if (sameframes == 0 && frames > 100) {
			// assume this is CBR MP3
			size = samplerate * 2 * (isstereo ? 2 : 1) * ((zfile_size (zf) - firstframe) / ((samplerate / 8 * bitrate) / freq));
			break;
		}
	}
	return size;
}