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authorJ. Alexander Treuman <jat@spatialrift.net>2006-07-18 18:18:02 +0000
committerJ. Alexander Treuman <jat@spatialrift.net>2006-07-18 18:18:02 +0000
commit6ea0ba392a3bc595e0612d5b53916dc2d564c71a (patch)
treefd6ee2b511c9095e6122f365a8e4b98f1e9e2113
parente7566b9643aab9d1776a4db59a17ce7b3eb6b3ce (diff)
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Cleaned up parse_xing, added support for Info magic, and added a parse_extension_headers function for when LAME tag support is added
git-svn-id: https://svn.musicpd.org/mpd/trunk@4398 09075e82-0dd4-0310-85a5-a0d7c8717e4f
-rw-r--r--src/inputPlugins/mp3_plugin.c69
1 files changed, 54 insertions, 15 deletions
diff --git a/src/inputPlugins/mp3_plugin.c b/src/inputPlugins/mp3_plugin.c
index 02c1733d9..4ba2ee539 100644
--- a/src/inputPlugins/mp3_plugin.c
+++ b/src/inputPlugins/mp3_plugin.c
@@ -402,16 +402,24 @@ static int decodeNextFrame(mp3DecodeData * data) {
return DECODE_OK;
}
-/* xing stuff stolen from alsaplayer */
+/* xing stuff stolen from alsaplayer, and heavily modified by jat */
#define XI_MAGIC (('X' << 8) | 'i')
#define NG_MAGIC (('n' << 8) | 'g')
+#define IN_MAGIC (('I' << 8) | 'n')
+#define FO_MAGIC (('f' << 8) | 'o')
+
+enum xing_magic {
+ XING_MAGIC_XING, /* VBR */
+ XING_MAGIC_INFO, /* CBR */
+};
struct xing {
long flags; /* valid fields (see below) */
unsigned long frames; /* total number of frames */
unsigned long bytes; /* total number of bytes */
unsigned char toc[100]; /* 100-point seek table */
- long scale; /* ?? */
+ long scale; /* VBR quality */
+ enum xing_magic magic; /* header magic */
};
enum {
@@ -421,54 +429,84 @@ enum {
XING_SCALE = 0x00000008L
};
-static int parse_xing(struct xing *xing, struct mad_bitptr ptr, unsigned int bitlen)
+static int parse_xing(struct xing *xing, struct mad_bitptr *ptr, int bitlen)
{
unsigned long bits;
+ int oldbitlen;
+ int bitsleft;
+ int i;
+
+ oldbitlen = bitlen;
if (bitlen < 16) goto fail;
- bits = mad_bit_read(&ptr, 16);
+ bits = mad_bit_read(ptr, 16);
bitlen -= 16;
if (bits == XI_MAGIC) {
if (bitlen < 16) goto fail;
- if (mad_bit_read(&ptr, 16) != NG_MAGIC) goto fail;
+ if (mad_bit_read(ptr, 16) != NG_MAGIC) goto fail;
bitlen -= 16;
+ xing->magic = XING_MAGIC_XING;
+ } else if (bits == IN_MAGIC) {
+ if (bitlen < 16) goto fail;
+ if (mad_bit_read(ptr, 16) != FO_MAGIC) goto fail;
+ bitlen -= 16;
+ xing->magic = XING_MAGIC_INFO;
}
- else if (bits != NG_MAGIC) goto fail;
+ else if (bits == NG_MAGIC) xing->magic = XING_MAGIC_XING;
+ else if (bits == FO_MAGIC) xing->magic = XING_MAGIC_INFO;
+ else goto fail;
if (bitlen < 32) goto fail;
- xing->flags = mad_bit_read(&ptr, 32);
+ xing->flags = mad_bit_read(ptr, 32);
bitlen -= 32;
if (xing->flags & XING_FRAMES) {
if (bitlen < 32) goto fail;
- xing->frames = mad_bit_read(&ptr, 32);
+ xing->frames = mad_bit_read(ptr, 32);
bitlen -= 32;
}
if (xing->flags & XING_BYTES) {
if (bitlen < 32) goto fail;
- xing->bytes = mad_bit_read(&ptr, 32);
+ xing->bytes = mad_bit_read(ptr, 32);
bitlen -= 32;
}
if (xing->flags & XING_TOC) {
- int i;
if (bitlen < 800) goto fail;
- for (i = 0; i < 100; ++i) xing->toc[i] = mad_bit_read(&ptr, 8);
+ for (i = 0; i < 100; ++i) xing->toc[i] = mad_bit_read(ptr, 8);
bitlen -= 800;
}
if (xing->flags & XING_SCALE) {
if (bitlen < 32) goto fail;
- xing->scale = mad_bit_read(&ptr, 32);
+ xing->scale = mad_bit_read(ptr, 32);
bitlen -= 32;
}
- return 1;
+ /* Make sure we consume no less than 120 bytes (960 bits) in hopes that
+ * the LAME tag is found there, and not right after the Xing header */
+ bitsleft = 960-(oldbitlen-bitlen);
+ if (bitsleft < 0) goto fail;
+ else if (bitsleft > 0) {
+ mad_bit_read(ptr, bitsleft);
+ bitlen -= bitsleft;
+ }
+
+ return bitlen;
fail:
xing->flags = 0;
- return 0;
+ return -1;
+}
+
+static int parse_extension_headers(struct xing *xing, struct mad_bitptr ptr,
+ int bitlen)
+{
+ bitlen = parse_xing(xing, &ptr, bitlen);
+ if (bitlen < 0) return 0;
+
+ return 1;
}
static int decodeFirstFrame(mp3DecodeData * data, DecoderControl * dc,
@@ -493,7 +531,8 @@ static int decodeFirstFrame(mp3DecodeData * data, DecoderControl * dc,
if(!skip && ret==DECODE_OK) break;
}
- if(parse_xing(&xing,data->stream.anc_ptr,data->stream.anc_bitlen)) {
+ if(parse_extension_headers(&xing, data->stream.anc_ptr,
+ (int)data->stream.anc_bitlen)) {
if(xing.flags & XING_FRAMES) {
mad_timer_t duration = data->frame.header.duration;
mad_timer_multiply(&duration,xing.frames);