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-rw-r--r--firmware/mp3data.c187
1 files changed, 84 insertions, 103 deletions
diff --git a/firmware/mp3data.c b/firmware/mp3data.c
index 6f4c560578..c2d4cd2c37 100644
--- a/firmware/mp3data.c
+++ b/firmware/mp3data.c
@@ -31,6 +31,7 @@
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
+#include <limits.h>
#include "debug.h"
#include "logf.h"
#include "mp3data.h"
@@ -39,7 +40,7 @@
#define DEBUG_VERBOSE
-#define BYTES2INT(b1,b2,b3,b4) (((long)(b1 & 0xFF) << (3*8)) | \
+#define BYTES2INT(b1,b2,b3,b4) (((long)(b1 & 0xFF) << (3*8)) | \
((long)(b2 & 0xFF) << (2*8)) | \
((long)(b3 & 0xFF) << (1*8)) | \
((long)(b4 & 0xFF) << (0*8)))
@@ -58,37 +59,34 @@
#define ORIGINAL_MASK (1L << 2)
#define EMPHASIS_MASK 3L
-/* Table of bitrates for MP3 files, all values in kilo.
- * Indexed by version, layer and value of bit 15-12 in header.
- */
-const int bitrate_table[2][3][16] =
-{
- {
- {0,32,64,96,128,160,192,224,256,288,320,352,384,416,448,0},
- {0,32,48,56, 64,80, 96, 112,128,160,192,224,256,320,384,0},
- {0,32,40,48, 56,64, 80, 96, 112,128,160,192,224,256,320,0}
- },
- {
- {0,32,48,56,64,80,96,112,128,144,160,176,192,224,256,0},
- {0, 8,16,24,32,40,48, 56, 64, 80, 96,112,128,144,160,0},
- {0, 8,16,24,32,40,48, 56, 64, 80, 96,112,128,144,160,0}
- }
+/* MPEG Version table, sorted by version index */
+static const signed char version_table[4] = {
+ MPEG_VERSION2_5, -1, MPEG_VERSION2, MPEG_VERSION1
};
-/* Table of samples per frame for MP3 files.
- * Indexed by layer. Multiplied with 1000.
- */
-const long bs[3] = {384000, 1152000, 1152000};
+/* Bitrate table for mpeg audio, indexed by row index and birate index */
+static const short bitrates[5][16] = {
+ {0,32,64,96,128,160,192,224,256,288,320,352,384,416,448,0}, /* V1 L1 */
+ {0,32,48,56, 64, 80, 96,112,128,160,192,224,256,320,384,0}, /* V1 L2 */
+ {0,32,40,48, 56, 64, 80, 96,112,128,160,192,224,256,320,0}, /* V1 L3 */
+ {0,32,48,56, 64, 80, 96,112,128,144,160,176,192,224,256,0}, /* V2 L1 */
+ {0, 8,16,24, 32, 40, 48, 56, 64, 80, 96,112,128,144,160,0} /* V2 L2+L3 */
+};
-/* Table of sample frequency for MP3 files.
- * Indexed by version and layer.
- */
+/* Bitrate pointer table, indexed by version and layer */
+static const short *bitrate_table[3][3] =
+{
+ {bitrates[0], bitrates[1], bitrates[2]},
+ {bitrates[3], bitrates[4], bitrates[4]},
+ {bitrates[3], bitrates[4], bitrates[4]}
+};
-const int freqtab[][4] =
+/* Sampling frequency table, indexed by version and frequency index */
+static const long freq_table[3][3] =
{
- {11025, 12000, 8000, 0}, /* MPEG version 2.5 */
- {44100, 48000, 32000, 0}, /* MPEG Version 1 */
- {22050, 24000, 16000, 0}, /* MPEG version 2 */
+ {44100, 48000, 32000}, /* MPEG Version 1 */
+ {22050, 24000, 16000}, /* MPEG version 2 */
+ {11025, 12000, 8000}, /* MPEG version 2.5 */
};
/* check if 'head' is a valid mp3 frame header */
@@ -117,97 +115,77 @@ static bool is_mp3frameheader(unsigned long head)
static bool mp3headerinfo(struct mp3info *info, unsigned long header)
{
- int bittable = 0;
- int bitindex;
- int freqindex;
-
+ int bitindex, freqindex;
+
/* MPEG Audio Version */
- switch((header & VERSION_MASK) >> 19) {
- case 0:
- /* MPEG version 2.5 is not an official standard */
- info->version = MPEG_VERSION2_5;
- bittable = MPEG_VERSION2 - 1; /* use the V2 bit rate table */
- break;
-
- case 1:
+ info->version = version_table[(header & VERSION_MASK) >> 19];
+ if (info->version < 0)
return false;
- case 2:
- /* MPEG version 2 (ISO/IEC 13818-3) */
- info->version = MPEG_VERSION2;
- bittable = MPEG_VERSION2 - 1;
- break;
-
- case 3:
- /* MPEG version 1 (ISO/IEC 11172-3) */
- info->version = MPEG_VERSION1;
- bittable = MPEG_VERSION1 - 1;
- break;
- }
-
- switch((header & LAYER_MASK) >> 17) {
- case 0:
+ /* Layer */
+ info->layer = 3 - ((header & LAYER_MASK) >> 17);
+ if (info->layer == 3)
return false;
- case 1:
- info->layer = 2;
- break;
- case 2:
- info->layer = 1;
- break;
- case 3:
- info->layer = 0;
- break;
- }
- info->protection = (header & PROTECTION_MASK)?true:false;
+ info->protection = (header & PROTECTION_MASK) ? true : false;
/* Bitrate */
- bitindex = (header & 0xf000) >> 12;
- info->bitrate = bitrate_table[bittable][info->layer][bitindex];
+ bitindex = (header & BITRATE_MASK) >> 12;
+ info->bitrate = bitrate_table[info->version][info->layer][bitindex];
if(info->bitrate == 0)
return false;
-
+
/* Sampling frequency */
- freqindex = (header & 0x0C00) >> 10;
- info->frequency = freqtab[info->version][freqindex];
- if(info->frequency == 0)
+ freqindex = (header & SAMPLERATE_MASK) >> 10;
+ if (freqindex == 3)
return false;
+ info->frequency = freq_table[info->version][freqindex];
- info->padding = (header & 0x0200)?1:0;
+ info->padding = (header & PADDING_MASK) ? 1 : 0;
/* Calculate number of bytes, calculation depends on layer */
- switch(info->layer) {
- case 0:
- info->frame_size = info->bitrate * 48000;
- info->frame_size /=
- freqtab[info->version][freqindex] << bittable;
- break;
- case 1:
- case 2:
- info->frame_size = info->bitrate * 144000;
- info->frame_size /=
- freqtab[info->version][freqindex] << bittable;
- break;
- default:
- info->frame_size = 1;
+ if (info->layer == 0) {
+ info->frame_samples = 384;
+ info->frame_size = (12000 * info->bitrate / info->frequency
+ + info->padding) * 4;
+ }
+ else {
+ if ((info->version > MPEG_VERSION1) && (info->layer == 2))
+ info->frame_samples = 576;
+ else
+ info->frame_samples = 1152;
+ info->frame_size = (1000/8) * info->frame_samples * info->bitrate
+ / info->frequency + info->padding;
}
- info->frame_size += info->padding;
-
- /* Calculate time per frame */
- info->frame_time = bs[info->layer] /
- (freqtab[info->version][freqindex] << bittable);
+ /* Frametime fraction calculation.
+ This fraction is reduced as far as possible. */
+ if (freqindex != 0) { /* 48/32/24/16/12/8 kHz */
+ /* integer number of milliseconds, denominator == 1 */
+ info->ft_num = 1000 * info->frame_samples / info->frequency;
+ info->ft_den = 1;
+ }
+ else { /* 44.1/22.05/11.025 kHz */
+ if (info->layer == 0) {
+ info->ft_num = 147000 * 384 / info->frequency;
+ info->ft_den = 147;
+ }
+ else {
+ info->ft_num = 49000 * info->frame_samples / info->frequency;
+ info->ft_den = 49;
+ }
+ }
- info->channel_mode = (header & 0xc0) >> 6;
- info->mode_extension = (header & 0x30) >> 4;
- info->emphasis = header & 3;
+ info->channel_mode = (header & CHANNELMODE_MASK) >> 6;
+ info->mode_extension = (header & MODE_EXT_MASK) >> 4;
+ info->emphasis = header & EMPHASIS_MASK;
#ifdef DEBUG_VERBOSE
- DEBUGF( "Header: %08x, Ver %d, lay %d, bitr %d, freq %d, "
- "chmode %d, mode_ext %d, emph %d, bytes: %d time: %d\n",
+ DEBUGF( "Header: %08x, Ver %d, lay %d, bitr %d, freq %ld, "
+ "chmode %d, mode_ext %d, emph %d, bytes: %d time: %d/%d\n",
header, info->version, info->layer+1, info->bitrate,
info->frequency, info->channel_mode, info->mode_extension,
- info->emphasis, info->frame_size, info->frame_time);
+ info->emphasis, info->frame_size, info->ft_num, info->ft_den);
#endif
return true;
}
@@ -252,7 +230,7 @@ static unsigned long __find_next_frame(int fd, long *offset, long max_offset,
if(*offset)
DEBUGF("Warning: skipping %d bytes of garbage\n", *offset);
#endif
-
+
return header;
}
@@ -380,9 +358,6 @@ int get_mp3file_info(int fd, struct mp3info *info)
memset(info, 0, sizeof(struct mp3info));
/* These two are needed for proper LAME gapless MP3 playback */
- /* TODO: These can be found in a LAME Info header as well, but currently
- they are only looked for in a Xing header. Xing and Info headers have
- the exact same format, but Info headers are used for CBR files. */
info->enc_delay = -1;
info->enc_padding = -1;
if(!mp3headerinfo(info, header))
@@ -435,7 +410,10 @@ int get_mp3file_info(int fd, struct mp3info *info)
{
info->frame_count = BYTES2INT(vbrheader[i], vbrheader[i+1],
vbrheader[i+2], vbrheader[i+3]);
- info->file_time = info->frame_count * info->frame_time;
+ if (info->frame_count <= ULONG_MAX / info->ft_num)
+ info->file_time = info->frame_count * info->ft_num / info->ft_den;
+ else
+ info->file_time = info->frame_count / info->ft_den * info->ft_num;
i += 4;
}
@@ -510,7 +488,10 @@ int get_mp3file_info(int fd, struct mp3info *info)
vbrheader[12], vbrheader[13]);
info->frame_count = BYTES2INT(vbrheader[14], vbrheader[15],
vbrheader[16], vbrheader[17]);
- info->file_time = info->frame_count * info->frame_time;
+ if (info->frame_count <= ULONG_MAX / info->ft_num)
+ info->file_time = info->frame_count * info->ft_num / info->ft_den;
+ else
+ info->file_time = info->frame_count / info->ft_den * info->ft_num;
info->bitrate = info->byte_count * 8 / info->file_time;
/* We don't parse the TOC, since we don't yet know how to (FIXME) */
generated by cgit (git 2.34.1) at 2023-12-07 16:16:50 +0000