vorbisdec: Accept 0 amplitude_bits

The specification does not prevent an encoder to write the amplitude 0
as 0 amplitude_bits.

Our get_bits() implementation might not support a zero sized read
properly, thus the additional branch.
(cherry picked from commit 23bd9ef4b2)

Conflicts:

	libavcodec/vorbisdec.c
This commit is contained in:
Luca Barbato
2013-02-24 16:56:15 +01:00
committed by Reinhard Tartler
parent 494ddd377a
commit c6c4dc6935

View File

@@ -603,13 +603,6 @@ static int vorbis_parse_setup_hdr_floors(vorbis_context *vc)
return AVERROR_INVALIDDATA;
}
floor_setup->data.t0.amplitude_bits = get_bits(gb, 6);
/* zero would result in a div by zero later *
* 2^0 - 1 == 0 */
if (floor_setup->data.t0.amplitude_bits == 0) {
av_log(vc->avccontext, AV_LOG_ERROR,
"Floor 0 amplitude bits is 0.\n");
return AVERROR_INVALIDDATA;
}
floor_setup->data.t0.amplitude_offset = get_bits(gb, 8);
floor_setup->data.t0.num_books = get_bits(gb, 4) + 1;
@@ -1063,6 +1056,9 @@ static int vorbis_floor0_decode(vorbis_context *vc,
unsigned amplitude, book_idx;
unsigned blockflag = vc->modes[vc->mode_number].blockflag;
if (!vf->amplitude_bits)
return 1;
amplitude = get_bits(&vc->gb, vf->amplitude_bits);
if (amplitude > 0) {
float last = 0;