Diffstat (limited to 'core/multimedia/opieplayer/libmpeg3/audio/header.c') (more/less context) (ignore whitespace changes)
| -rw-r--r-- | core/multimedia/opieplayer/libmpeg3/audio/header.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/core/multimedia/opieplayer/libmpeg3/audio/header.c b/core/multimedia/opieplayer/libmpeg3/audio/header.c new file mode 100644 index 0000000..02b5e7c --- a/dev/null +++ b/core/multimedia/opieplayer/libmpeg3/audio/header.c @@ -0,0 +1,163 @@ +#include "mpeg3audio.h" +#include "tables.h" +#include "../libmpeg3.h" +#include "../mpeg3protos.h" + +#include <stdio.h> + +/* Return 1 if the head check doesn't find a header. */ +int mpeg3audio_head_check(unsigned long head) +{ + if((head & 0xffe00000) != 0xffe00000) return 1; + if(!((head >> 17) & 3)) return 1; + if(((head >> 12) & 0xf) == 0xf) return 1; + if(!((head >> 12) & 0xf)) return 1; + if(((head >> 10) & 0x3) == 0x3 ) return 1; + if(((head >> 19) & 1) == 1 && ((head >> 17) & 3) == 3 && ((head >> 16) & 1) == 1) + return 1; + if((head & 0xffff0000) == 0xfffe0000) return 1; + + return 0; +} + +int mpeg3audio_decode_header(mpeg3audio_t *audio) +{ + if(audio->newhead & (1 << 20)) + { + audio->lsf = (audio->newhead & (1 << 19)) ? 0x0 : 0x1; + audio->mpeg35 = 0; + } + else + { + audio->lsf = 1; + audio->mpeg35 = 1; + } + + audio->layer = 4 - ((audio->newhead >> 17) & 3); + if(audio->mpeg35) + audio->sampling_frequency_code = 6 + ((audio->newhead >> 10) & 0x3); + else + audio->sampling_frequency_code = ((audio->newhead >> 10) & 0x3) + (audio->lsf * 3); + + audio->error_protection = ((audio->newhead >> 16) & 0x1) ^ 0x1; + + audio->bitrate_index = ((audio->newhead >> 12) & 0xf); + audio->padding = ((audio->newhead >> 9) & 0x1); + audio->extension = ((audio->newhead >> 8) & 0x1); + audio->mode = ((audio->newhead >> 6) & 0x3); + audio->mode_ext = ((audio->newhead >> 4) & 0x3); + audio->copyright = ((audio->newhead >> 3) & 0x1); + audio->original = ((audio->newhead >> 2) & 0x1); + audio->emphasis = audio->newhead & 0x3; + audio->channels = (audio->mode == MPG_MD_MONO) ? 1 : 2; + if(audio->channels > 1) + audio->single = -1; + else + audio->single = 3; + + audio->prev_framesize = audio->framesize; + + if(!audio->bitrate_index) return 1; + audio->bitrate = 1000 * mpeg3_tabsel_123[audio->lsf][audio->layer - 1][audio->bitrate_index]; + + switch(audio->layer) + { + case 1: + audio->framesize = (long)mpeg3_tabsel_123[audio->lsf][0][audio->bitrate_index] * 12000; + audio->framesize /= mpeg3_freqs[audio->sampling_frequency_code]; + audio->framesize = ((audio->framesize + audio->padding) << 2) - 4; + break; + case 2: + audio->framesize = (long)mpeg3_tabsel_123[audio->lsf][1][audio->bitrate_index] * 144000; + audio->framesize /= mpeg3_freqs[audio->sampling_frequency_code]; + audio->framesize += audio->padding - 4; + break; + case 3: + if(audio->lsf) + audio->ssize = (audio->channels == 1) ? 9 : 17; + else + audio->ssize = (audio->channels == 1) ? 17 : 32; + if(audio->error_protection) + audio->ssize += 2; + audio->framesize = (long)mpeg3_tabsel_123[audio->lsf][2][audio->bitrate_index] * 144000; + audio->framesize /= mpeg3_freqs[audio->sampling_frequency_code] << (audio->lsf); + audio->framesize = audio->framesize + audio->padding - 4; + break; + default: + return 1; + } + + if(audio->framesize > MAXFRAMESIZE) return 1; + + return 0; +} + +int mpeg3audio_read_frame_body(mpeg3audio_t *audio) +{ + int i; + for(i = 0; i < audio->framesize; i++) + { + audio->bsbuf[i] = mpeg3bits_getbits(audio->astream, 8); + } + return 0; +} + +/* Seek to the start of the previous header */ +int mpeg3audio_prev_header(mpeg3audio_t *audio) +{ + int result = 0, i, len = (int)audio->avg_framesize; + + for(i = 0; i < len && !result; i++) + { + mpeg3bits_getbits_reverse(audio->astream, 8); + } +/* Get reading in the forward direction again. */ + result |= mpeg3bits_refill(audio->astream); + return result; +} + +/* Read the next header */ +int mpeg3audio_read_header(mpeg3audio_t *audio) +{ + unsigned int code; + int i; + int attempt = 0; + int result = 0; + + switch(audio->format) + { + case AUDIO_AC3: + result = mpeg3audio_read_ac3_header(audio); + break; + + case AUDIO_MPEG: +/* Layer 1 not supported */ + if(audio->layer == 1) + { + fprintf(stderr, "mpeg3audio_new: layer 1 not supported\n"); + result = 1; + } + audio->newhead = mpeg3bits_showbits(audio->astream, 32); + if(!mpeg3bits_eof(audio->astream) && + (mpeg3audio_head_check(audio->newhead) || mpeg3audio_decode_header(audio))) + { + do + { + attempt++; + mpeg3bits_getbyte_noptr(audio->astream); + audio->newhead = mpeg3bits_showbits(audio->astream, 32); + }while(!mpeg3bits_eof(audio->astream) && + attempt < 65536 && + (mpeg3audio_head_check(audio->newhead) || mpeg3audio_decode_header(audio))); + } + +/* Skip the 4 bytes containing the header */ + mpeg3bits_getbits(audio->astream, 32); + break; + + case AUDIO_PCM: + mpeg3audio_read_pcm_header(audio); + break; + } + return mpeg3bits_eof(audio->astream); +} |