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--- getbits.c.orig 1997-08-20 13:30:21 UTC
+++ getbits.c
@@ -91,6 +91,7 @@ unsigned int getbits(int n)
*/
static inline void parse_header(struct AUDIO_HEADER *header)
{
+ header->IDex=_getbits(1);
header->ID=_getbits(1);
header->layer=_getbits(2);
header->protection_bit=_getbits(1);
@@ -112,11 +113,17 @@ static inline int header_sanity_check(st
header->bitrate_index==15 ||
header->sampling_frequency==3) return -1;
+ /* Rule out invalid MPEG 2.5 headers */
+ if (header->IDex==0 &&
+ (header->ID==1 || header->layer!=1 ||
+ header->bitrate_index > 8)) return -1;
+
/* an additional check to make shure that stuffing never gets mistaken
* for a syncword. This rules out some legal layer1 streams, but who
* cares about layer1 anyway :-). I must get this right sometime.
*/
if ( header->ID==1 && header->layer==3 && header->protection_bit==1) return -1;
+
return 0;
}
@@ -132,11 +139,7 @@ struct AUDIO_HEADER tmp;
if ((retval=_fillbfr(4))!=0) return retval;
for(;;) {
- while ((s=_getbits(12)) != 0xfff) {
- if (s==0xffe) {
- parse_header(&tmp);
- if (header_sanity_check(&tmp)==0) return GETHDR_NS;
- }
+ while (_getbits(11) != 0x7ff) {
if ((retval=readsync())!=0) return retval;
}
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