--- /dev/null
+/* mp3.c
+ Routines for handling .mp3 files
+
+ Part of the swftools package.
+
+ Copyright (c) 2005 Joel Yliluoma <bisqwit@iki.fi>
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "mp3.h"
+
+struct MP3Frame
+{
+ unsigned bitrate;
+ unsigned samprate;
+ unsigned chanmode;
+ unsigned framesize;
+ unsigned char* data;
+ struct MP3Frame* next;
+};
+
+// 0 4 8 C
+static const unsigned BR_mpeg1[16] = {0,32,40,48,56,64,80,96,112,128,160,192,224,256,320,0};
+static const unsigned BR_mpeg2[16] = {0,8, 16,24,32,40,48,56, 64, 80, 96,112,128,144,160,0};
+static const unsigned BR_reserved[16] = {0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0};
+static const unsigned*const BR[4] = {BR_mpeg2, BR_reserved, BR_mpeg2, BR_mpeg1};
+
+static const unsigned SR_mpeg1[4] = {44100,48000,32000,0};
+static const unsigned SR_mpeg2[4] = {22050,24000,16000,0};
+static const unsigned SR_mpeg25[4] = {11025,12000,8000,0};
+static const unsigned SR_reserved[4] = {0,0,0,0};
+static const unsigned*const SR[4] = {SR_mpeg25, SR_reserved, SR_mpeg2, SR_mpeg1};
+
+int mp3_read(struct MP3*mp3, char* filename)
+{
+ struct MP3Frame* root = 0;
+ struct MP3Frame** cur = &root;
+
+ unsigned totalsize = 0;
+ unsigned first_samprate = 0;
+ unsigned nframes = 0;
+ int first_chanmode = -1;
+
+ FILE*fi = fopen(filename, "rb");
+ if(!fi) return 0;
+
+ for(;;)
+ {
+ unsigned char FrameBuf[2048];
+ unsigned char* hdr = FrameBuf;
+ unsigned char* data = FrameBuf+4;
+ unsigned char* frdata;
+
+ unsigned char mpegver;
+ unsigned padding;
+ unsigned bitrate;
+ unsigned samprate;
+ unsigned framesize;
+ int chanmode;
+
+ if(fread(hdr,1,4,fi) < 4) break;
+ if(hdr[0] != 0xFF
+ || (hdr[1] & 0xE0) != 0xE0)
+ {
+ fprintf(stderr, "readMP3: invalid header %02X %02X %02X %02X\n",
+ hdr[0],hdr[1],hdr[2],hdr[3]);
+ break;
+ }
+
+ mpegver = (hdr[1] >> 3) & 0x03;
+
+ bitrate = BR[mpegver][ (hdr[2] >> 4) & 0x0F ] * 1000;
+ samprate = SR[mpegver][ (hdr[2] >> 2) & 0x03 ];
+ chanmode = (hdr[3] >> 6) & 0x03;
+
+ padding = (hdr[2] & 2) ? 1 : 0;
+
+ if(!bitrate || !samprate)
+ {
+ /* Invalid frame */
+ /*break;*/
+ }
+ if(!first_samprate) first_samprate = samprate;
+ else if(first_samprate != samprate)
+ {
+ /* Sampling rate changed?!? */
+ fprintf(stderr, "readMP3: sampling rate changed?\n");
+ /*break;*/
+ }
+ if(first_chanmode<0) first_chanmode = chanmode;
+ else if(first_chanmode != chanmode)
+ {
+ /* Channel mode changed?!? */
+ fprintf(stderr, "readMP3: chanmode changed?\n");
+ /*break;*/
+ }
+
+ framesize = ((mpegver == 3 ? 144 : 72) * bitrate) / samprate + padding;
+
+/*
+ fprintf(stderr, "%02X %02X %02X %02X - bitrate=%u,samprate=%u,chanmode=%u,padding=%u,framesize=%u\n",
+ hdr[0],hdr[1],hdr[2],hdr[3],bitrate,samprate,chanmode,padding,framesize);
+*/
+ if(framesize > sizeof(FrameBuf)) break;
+ if(fread(data, 1, framesize - 4, fi) < framesize-4)
+ {
+ fprintf(stderr, "readMP3: short read at frame %u\n", nframes);
+ break;
+ }
+
+ if(!bitrate || !samprate) continue;
+
+ frdata = (unsigned char*)malloc(framesize);
+ if(!frdata)
+ {
+ fprintf(stderr, "readMP3: malloc failed\n");
+ break;
+ }
+
+ *cur = (struct MP3Frame*)malloc(sizeof(*root));
+ if(!*cur)
+ {
+ fprintf(stderr, "readMP3: malloc failed\n");
+ free(frdata);
+ break;
+ }
+
+ (*cur)->next = 0;
+ (*cur)->bitrate = bitrate;
+ (*cur)->samprate = samprate;
+ (*cur)->chanmode = chanmode;
+ (*cur)->framesize = framesize;
+ (*cur)->data = frdata;
+
+ memcpy(frdata, FrameBuf, framesize);
+ cur = &(*cur)->next;
+
+ totalsize += framesize;
+ ++nframes;
+ }
+ if(!root)
+ {
+ fprintf(stderr, "readMP3: not a MP3 file\n");
+ return 0;
+ }
+
+ /*
+ fprintf(stderr, "readMP3: read %u frames (%u bytes)\n", nframes, totalsize);
+ */
+
+ mp3->SampRate = first_samprate;
+ mp3->Channels = first_chanmode == 3 ? 1 : 2;
+ mp3->NumFrames = nframes;
+ mp3->size = totalsize;
+ mp3->data = (unsigned char*)malloc(mp3->size);
+ if(mp3->data)
+ {
+ unsigned pos=0;
+ struct MP3Frame* it;
+ for(it=root; it; it=it->next)
+ {
+ memcpy(mp3->data + pos, it->data, it->framesize);
+ pos += it->framesize;
+ }
+ }
+ else
+ {
+ fprintf(stderr, "readMP3: malloc failed\n");
+ }
+
+ while(root)
+ {
+ struct MP3Frame* next = root->next;
+ free(root->data);
+ free(root);
+ root = next;
+ }
+
+ return mp3->data != NULL;
+}
+
+void mp3_clear(struct MP3*mp3)
+{
+ free(mp3->data);
+ mp3->data = 0;
+}
+
+
git.asbjorn.biz / swftools.git / blobdiff