From a057ef6923fba7947d8ccf27b751bf91fde3a755 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Thu, 1 Mar 2012 06:07:36 +0100 Subject: [PATCH] mpegaudiodec: change granule skip code to avoid false checked bitstream reader errors. Code ported from qatar/master, please see there for per line authorship. Main authors AFAIK are Ronald and Justin. I have no authorship on this. Signed-off-by: Michael Niedermayer --- libavcodec/mpegaudiodec.c | 35 ++++++++++++++++++++--------------- 1 file changed, 20 insertions(+), 15 deletions(-) diff --git a/libavcodec/mpegaudiodec.c b/libavcodec/mpegaudiodec.c index 00565875fc..ddb7695446 100644 --- a/libavcodec/mpegaudiodec.c +++ b/libavcodec/mpegaudiodec.c @@ -1386,6 +1386,7 @@ static int mp_decode_layer3(MPADecodeContext *s) } if (!s->adu_mode) { + int skip; const uint8_t *ptr = s->gb.buffer + (get_bits_count(&s->gb)>>3); int extrasize = av_clip(get_bits_left(&s->gb) >> 3, 0, EXTRABYTES); assert((get_bits_count(&s->gb) & 7) == 0); @@ -1399,25 +1400,29 @@ static int mp_decode_layer3(MPADecodeContext *s) #if !UNCHECKED_BITSTREAM_READER s->gb.size_in_bits_plus8 += FFMAX(extrasize, LAST_BUF_SIZE - s->last_buf_size) * 8; #endif - skip_bits_long(&s->gb, 8*(s->last_buf_size - main_data_begin)); + s->last_buf_size <<= 3; + for (gr = 0; gr < nb_granules && (s->last_buf_size >> 3) < main_data_begin; gr++) { + for (ch = 0; ch < s->nb_channels; ch++) { + g = &s->granules[ch][gr]; + s->last_buf_size += g->part2_3_length; + memset(g->sb_hybrid, 0, sizeof(g->sb_hybrid)); + } + } + skip = s->last_buf_size - 8 * main_data_begin; + if (skip >= s->gb.size_in_bits && s->in_gb.buffer) { + skip_bits_long(&s->in_gb, skip - s->gb.size_in_bits); + s->gb = s->in_gb; + s->in_gb.buffer = NULL; + } else { + skip_bits_long(&s->gb, skip); + } + } else { + gr = 0; } - for (gr = 0; gr < nb_granules; gr++) { + for (; gr < nb_granules; gr++) { for (ch = 0; ch < s->nb_channels; ch++) { g = &s->granules[ch][gr]; - if (get_bits_count(&s->gb) < 0) { - av_log(s->avctx, AV_LOG_DEBUG, "mdb:%d, lastbuf:%d skipping granule %d\n", - main_data_begin, s->last_buf_size, gr); - skip_bits_long(&s->gb, g->part2_3_length); - memset(g->sb_hybrid, 0, sizeof(g->sb_hybrid)); - if (get_bits_count(&s->gb) >= s->gb.size_in_bits && s->in_gb.buffer) { - skip_bits_long(&s->in_gb, get_bits_count(&s->gb) - s->gb.size_in_bits); - s->gb = s->in_gb; - s->in_gb.buffer = NULL; - } - continue; - } - bits_pos = get_bits_count(&s->gb); if (!s->lsf) {