Commit fdba370f authored by Mans Rullgard's avatar Mans Rullgard

h264: fix HRD parameters parsing

The bit_rate_value_minus1 and cpb_size_value_minus1 elements
allow a wider range than get_ue_golomb() supports.  This
adds a get_ue_golomb_long() function supporting up to 31
leading zeros, which is the maximum for these syntax
elements, and uses it in decode_hrd_parameters().
Signed-off-by: 's avatarMans Rullgard <mans@mansr.com>
parent 91f47329
......@@ -75,6 +75,20 @@ static inline int get_ue_golomb(GetBitContext *gb){
}
}
/**
* Read an unsigned Exp-Golomb code in the range 0 to UINT32_MAX-1.
*/
static inline unsigned get_ue_golomb_long(GetBitContext *gb)
{
unsigned buf, log;
buf = show_bits_long(gb, 32);
log = 31 - av_log2(buf);
skip_bits_long(gb, log);
return get_bits_long(gb, log + 1) - 1;
}
/**
* read unsigned exp golomb code, constraint to a max of 31.
* the return value is undefined if the stored value exceeds 31.
......
......@@ -130,8 +130,8 @@ static inline int decode_hrd_parameters(H264Context *h, SPS *sps){
get_bits(&s->gb, 4); /* bit_rate_scale */
get_bits(&s->gb, 4); /* cpb_size_scale */
for(i=0; i<cpb_count; i++){
get_ue_golomb(&s->gb); /* bit_rate_value_minus1 */
get_ue_golomb(&s->gb); /* cpb_size_value_minus1 */
get_ue_golomb_long(&s->gb); /* bit_rate_value_minus1 */
get_ue_golomb_long(&s->gb); /* cpb_size_value_minus1 */
get_bits1(&s->gb); /* cbr_flag */
}
sps->initial_cpb_removal_delay_length = get_bits(&s->gb, 5) + 1;
......
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