From 23bd9ef4b209c789d5473d75f89a2e411d343d80 Mon Sep 17 00:00:00 2001 From: Luca Barbato Date: Sun, 24 Feb 2013 16:56:15 +0100 Subject: [PATCH] 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. --- libavcodec/vorbisdec.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/libavcodec/vorbisdec.c b/libavcodec/vorbisdec.c index 7575ee4181..0513d972da 100644 --- a/libavcodec/vorbisdec.c +++ b/libavcodec/vorbisdec.c @@ -602,13 +602,6 @@ 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) { - 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; @@ -1059,6 +1052,9 @@ 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;