ref: 0ae65c429d96f8cae1a959e7b51294ea90aaa427
parent: fa4c2ef5d00c4a136e6b59873151dea46e8d8023
author: lieff <lieff@users.noreply.github.com>
date: Wed Feb 5 19:27:59 EST 2020
mp3dec_ex: better vbr tag detect
--- a/minimp3_ex.h
+++ b/minimp3_ex.h
@@ -129,7 +129,6 @@
static int mp3dec_check_vbrtag(const uint8_t *frame, int frame_size, uint32_t *frames, int *delay, int *padding)
{- int i;
static const char g_xing_tag[4] = { 'X', 'i', 'n', 'g' }; static const char g_info_tag[4] = { 'I', 'n', 'f', 'o' };#define FRAMES_FLAG 1
@@ -136,36 +135,43 @@
#define BYTES_FLAG 2
#define TOC_FLAG 4
#define VBR_SCALE_FLAG 8
- /* TODO: skip side-info?
- / Side info offsets afrer header:
+ /* Side info offsets afrer header:
/ Mono Stereo
/ MPEG1 17 32
/ MPEG2 & 2.5 9 17*/
- for (i = 5; i < frame_size - 36; i++)
- {- const uint8_t *tag = frame + i;
- if (memcmp(g_xing_tag, tag, 4) && memcmp(g_info_tag, tag, 4))
- continue;
- int flags = tag[7];
- if (!((flags & FRAMES_FLAG)))
- break;
- tag += 8;
- (*frames) = (uint32_t)(tag[0] << 24) | (tag[1] << 16) | (tag[2] << 8) | tag[3];
+ bs_t bs[1];
+ L3_gr_info_t gr_info[4];
+ bs_init(bs, frame + HDR_SIZE, frame_size - HDR_SIZE);
+ if (HDR_IS_CRC(frame))
+ get_bits(bs, 16);
+ if (L3_read_side_info(bs, gr_info, frame) < 0)
+ return 0; /* side info corrupted */
+
+ const uint8_t *tag = frame + HDR_SIZE + bs->pos/8;
+ if (memcmp(g_xing_tag, tag, 4) && memcmp(g_info_tag, tag, 4))
+ return 0;
+ int flags = tag[7];
+ if (!((flags & FRAMES_FLAG)))
+ return 0;
+ tag += 8;
+ *frames = (uint32_t)(tag[0] << 24) | (tag[1] << 16) | (tag[2] << 8) | tag[3];
+ tag += 4;
+ if (flags & BYTES_FLAG)
tag += 4;
- if (flags & BYTES_FLAG)
- tag += 4;
- if (flags & TOC_FLAG)
- tag += 100;
- if (flags & VBR_SCALE_FLAG)
- tag += 4;
+ if (flags & TOC_FLAG)
+ tag += 100;
+ if (flags & VBR_SCALE_FLAG)
+ tag += 4;
+ *delay = *padding = 0;
+ if (*tag)
+ { /* extension, LAME, Lavc, etc. Should be the same structure. */tag += 21;
- if (tag - frame + 2 >= frame_size)
- break;
+ if (tag - frame + 14 >= frame_size)
+ return 0;
*delay = ((tag[0] << 4) | (tag[1] >> 4)) + (528 + 1);
*padding = (((tag[1] & 0xF) << 8) | tag[2]) - (528 + 1);
- return 1;
}
- return 0;
+ return 1;
}
void mp3dec_load_buf(mp3dec_t *dec, const uint8_t *buf, size_t buf_size, mp3dec_file_info_t *info, MP3D_PROGRESS_CB progress_cb, void *user_data)