Author: alexc
Date: Thu Nov 26 22:52:50 2009
New Revision: 5457
Log:
Read SBR bits from a second GetBitContext to prevent unrecoverable over-reads
and get automatic under-read protection.
Modified:
aac-sbr/aacsbr.c
Modified: aac-sbr/aacsbr.c
==============================================================================
--- aac-sbr/aacsbr.c Fri Nov 20 21:48:49 2009 (r5456)
+++ aac-sbr/aacsbr.c Thu Nov 26 22:52:50 2009 (r5457)
@@ -792,9 +792,13 @@ static void sbr_reset(AACContext *ac, Sp
* @return Returns number of bytes consumed from the TYPE_FIL element.
*/
int ff_decode_sbr_extension(AACContext *ac, SpectralBandReplication *sbr,
- GetBitContext *gb, int crc, int cnt, int id_aac)
+ GetBitContext *gb_host, int crc, int cnt, int
id_aac)
{
unsigned int num_sbr_bits = 0, num_align_bits;
+ unsigned bytes_read;
+ GetBitContext gbc = *gb_host;
+ GetBitContext *gb = &gbc;
+ skip_bits_long(gb_host, cnt*8 - 4);
if (crc) {
skip_bits(gb, 10); // bs_sbr_crc_bits; FIXME - implement CRC check
@@ -812,9 +816,11 @@ int ff_decode_sbr_extension(AACContext *
num_sbr_bits += sbr_data(ac, sbr, gb, id_aac);
num_align_bits = ((cnt << 3) - 4 - num_sbr_bits) & 7;
- skip_bits(gb, num_align_bits); // bs_fill_bits
-
- return (num_sbr_bits + num_align_bits + 4) >> 3;
+ bytes_read = ((num_sbr_bits + num_align_bits + 4) / 8);
+ if (bytes_read > cnt) {
+ av_log(ac->avccontext, AV_LOG_ERROR, "Expected to read %d SBR bytes
actually read %d.\n", cnt, bytes_read);
+ }
+ return cnt;
}
// Time/frequency Grid (14496-3 sp04 p200)
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