X-Git-Url: https://notaz.gp2x.de/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=platform%2Fcommon%2Fmp3_helix.c;h=62e91897804680577ee9d7e9ce8d11ba46abd6cb;hb=fc11dd059b5c7369a51ddcca532505b588bd0030;hp=5f58aa5704ad853d924707a3291fcdab5fafbc23;hpb=7c34867ab6109c47ad099e903a57af6d2699074f;p=picodrive.git diff --git a/platform/common/mp3_helix.c b/platform/common/mp3_helix.c index 5f58aa5..62e9189 100644 --- a/platform/common/mp3_helix.c +++ b/platform/common/mp3_helix.c @@ -1,7 +1,11 @@ -// Some mp3 related code for Sega/Mega CD. -// Uses the Helix Fixed-point MP3 decoder - -// (c) Copyright 2007, Grazvydas "notaz" Ignotas +/* + * Some mp3 related code for Sega/Mega CD. + * Uses the Helix Fixed-point MP3 decoder + * (C) notaz, 2007-2009 + * + * This work is licensed under the terms of MAME license. + * See COPYING file in the top-level directory. + */ #include #include @@ -12,96 +16,15 @@ #include "mp3.h" #include "lprintf.h" -static HMP3Decoder mp3dec = 0; -static FILE *mp3_current_file = NULL; -static int mp3_file_len = 0, mp3_file_pos = 0; -static int mp3_buffer_offs = 0; -static unsigned char mp3_input_buffer[2*1024]; +static HMP3Decoder mp3dec; +static unsigned char mp3_input_buffer[2 * 1024]; #ifdef __GP2X__ #define mp3_update mp3_update_local #define mp3_start_play mp3_start_play_local #endif -static int find_sync_word(unsigned char *buf, int nBytes) -{ - unsigned char *p, *pe; - - /* find byte-aligned syncword - need 12 (MPEG 1,2) or 11 (MPEG 2.5) matching bits */ - for (p = buf, pe = buf + nBytes - 4; p < pe; p++) - { - int pn; - if (p[0] != 0xff) continue; - pn = p[1]; - if ((pn & 0xf8) != 0xf8 || // currently must be MPEG1 - (pn & 6) == 0) { // invalid layer - p++; continue; - } - pn = p[2]; - if ((pn & 0xf0) < 0x20 || (pn & 0xf0) == 0xf0 || // bitrates - (pn & 0x0c) != 0) { // not 44kHz - continue; - } - - return p - buf; - } - - return -1; -} - -static int try_get_header(unsigned char *buff, MP3FrameInfo *fi) -{ - int ret, offs1, offs = 0; - - while (1) - { - offs1 = find_sync_word(buff + offs, 2048 - offs); - if (offs1 < 0) return -2; - offs += offs1; - if (2048 - offs < 4) return -3; - - // printf("trying header %08x\n", *(int *)(buff + offs)); - - ret = MP3GetNextFrameInfo(mp3dec, fi, buff + offs); - if (ret == 0 && fi->bitrate != 0) break; - offs++; - } - - return ret; -} - -int mp3_get_bitrate(FILE *f, int len) -{ - unsigned char buff[2048]; - MP3FrameInfo fi; - int ret; - - memset(buff, 0, 2048); - - if (mp3dec) MP3FreeDecoder(mp3dec); - mp3dec = MP3InitDecoder(); - - fseek(f, 0, SEEK_SET); - ret = fread(buff, 1, 2048, f); - fseek(f, 0, SEEK_SET); - if (ret <= 0) return -1; - - ret = try_get_header(buff, &fi); - if (ret != 0 || fi.bitrate == 0) { - // try to read somewhere around the middle - fseek(f, len>>1, SEEK_SET); - fread(buff, 1, 2048, f); - fseek(f, 0, SEEK_SET); - ret = try_get_header(buff, &fi); - } - if (ret != 0) return ret; - - // printf("bitrate: %i\n", fi.bitrate / 1000); - - return fi.bitrate / 1000; -} - -static int mp3_decode(void) +int mp3dec_decode(FILE *f, int *file_pos, int file_len) { unsigned char *readPtr; int bytesLeft; @@ -111,16 +34,17 @@ static int mp3_decode(void) do { - if (mp3_file_pos >= mp3_file_len) + if (*file_pos >= file_len) return 1; /* EOF, nothing to do */ - fseek(mp3_current_file, mp3_file_pos, SEEK_SET); - bytesLeft = fread(mp3_input_buffer, 1, sizeof(mp3_input_buffer), mp3_current_file); + fseek(f, *file_pos, SEEK_SET); + bytesLeft = fread(mp3_input_buffer, 1, sizeof(mp3_input_buffer), f); - offset = find_sync_word(mp3_input_buffer, bytesLeft); + offset = mp3_find_sync_word(mp3_input_buffer, bytesLeft); if (offset < 0) { - lprintf("find_sync_word (%i/%i) err %i\n", mp3_file_pos, mp3_file_len, offset); - mp3_file_pos = mp3_file_len; + lprintf("find_sync_word (%i/%i) err %i\n", + *file_pos, file_len, offset); + *file_pos = file_len; return 1; // EOF } readPtr = mp3_input_buffer + offset; @@ -131,88 +55,41 @@ static int mp3_decode(void) if (err) { if (err == ERR_MP3_MAINDATA_UNDERFLOW && !had_err) { // just need another frame - mp3_file_pos += readPtr - mp3_input_buffer; + *file_pos += readPtr - mp3_input_buffer; continue; } if (err == ERR_MP3_INDATA_UNDERFLOW && !had_err) { if (offset == 0) // something's really wrong here, frame had to fit - mp3_file_pos = mp3_file_len; + *file_pos = file_len; else - mp3_file_pos += offset; + *file_pos += offset; continue; } if (-12 <= err && err <= -6) { // ERR_MP3_INVALID_FRAMEHEADER, ERR_MP3_INVALID_* // just try to skip the offending frame.. - mp3_file_pos += offset + 1; + *file_pos += offset + 1; continue; } - lprintf("MP3Decode err (%i/%i) %i\n", mp3_file_pos, mp3_file_len, err); - mp3_file_pos = mp3_file_len; + lprintf("MP3Decode err (%i/%i) %i\n", + *file_pos, file_len, err); + *file_pos = file_len; return 1; } - mp3_file_pos += readPtr - mp3_input_buffer; + *file_pos += readPtr - mp3_input_buffer; } while (0); return 0; } -void mp3_start_play(FILE *f, int pos) +int mp3dec_start(void) { - mp3_file_len = mp3_file_pos = 0; - mp3_current_file = NULL; - mp3_buffer_offs = 0; - - if (!(PicoOpt & POPT_EN_MCD_CDDA) || f == NULL) // cdda disabled or no file? - return; - // must re-init decoder for new track if (mp3dec) MP3FreeDecoder(mp3dec); mp3dec = MP3InitDecoder(); - mp3_current_file = f; - fseek(f, 0, SEEK_END); - mp3_file_len = ftell(f); - - // seek.. - if (pos) { - unsigned long long pos64 = mp3_file_len; - pos64 *= pos; - mp3_file_pos = pos64 >> 10; - } - - mp3_decode(); + return (mp3dec == 0) ? -1 : 0; } - -void mp3_update(int *buffer, int length, int stereo) -{ - int length_mp3, shr = 0; - void (*mix_samples)(int *dest_buf, short *mp3_buf, int count) = mix_16h_to_32; - - if (mp3_current_file == NULL || mp3_file_pos >= mp3_file_len) - return; /* no file / EOF */ - - length_mp3 = length; - if (PsndRate == 22050) { mix_samples = mix_16h_to_32_s1; length_mp3 <<= 1; shr = 1; } - else if (PsndRate == 11025) { mix_samples = mix_16h_to_32_s2; length_mp3 <<= 2; shr = 2; } - - if (1152 - mp3_buffer_offs >= length_mp3) { - mix_samples(buffer, cdda_out_buffer + mp3_buffer_offs*2, length<<1); - - mp3_buffer_offs += length_mp3; - } else { - int ret, left = 1152 - mp3_buffer_offs; - - mix_samples(buffer, cdda_out_buffer + mp3_buffer_offs*2, (left>>shr)<<1); - ret = mp3_decode(); - if (ret == 0) { - mp3_buffer_offs = length_mp3 - left; - mix_samples(buffer + ((left>>shr)<<1), cdda_out_buffer, (mp3_buffer_offs>>shr)<<1); - } else - mp3_buffer_offs = 0; - } -} -