Module: libav Branch: master Commit: 464f26889c99f194d112fcf1197795d341fad38b
Author: Ronald S. Bultje <[email protected]> Committer: Justin Ruggles <[email protected]> Date: Fri Dec 30 13:08:21 2011 -0800 mpegaudiodec: fix seeking. The safe bitstream reader does not allow using skip_bits_long() to seek to a point before the start of the buffer, which was needed by the mp3 decoder. This change instead calculates the start point of the first valid granule and skips to that position. Signed-off-by: Justin Ruggles <[email protected]> --- libavcodec/mpegaudiodec.c | 34 ++++++++++++++++++---------------- 1 files changed, 18 insertions(+), 16 deletions(-) diff --git a/libavcodec/mpegaudiodec.c b/libavcodec/mpegaudiodec.c index 63ae455..ad3b199 100644 --- a/libavcodec/mpegaudiodec.c +++ b/libavcodec/mpegaudiodec.c @@ -1551,25 +1551,27 @@ static int mp_decode_layer3(MPADecodeContext *s) #if !UNCHECKED_BITSTREAM_READER s->gb.size_in_bits_plus8 += EXTRABYTES * 8; #endif - skip_bits_long(&s->gb, 8*(s->last_buf_size - main_data_begin)); - } - - for (gr = 0; 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); + s->last_buf_size <<= 3; + for (gr = 0, ch = 0; gr < nb_granules && (s->last_buf_size >> 3) < main_data_begin; gr++, ch = 0) { + for (; ch < s->nb_channels && (s->last_buf_size >> 3) < main_data_begin; ch++) { + g = &s->granules[ch][gr]; + s->last_buf_size += 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; } + } + skip_bits_long(&s->gb, s->last_buf_size - 8 * main_data_begin); + 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; + } + } else { + gr = ch = 0; + } + for (; gr < nb_granules; gr++, ch = 0) { + for (; ch < s->nb_channels; ch++) { + g = &s->granules[ch][gr]; bits_pos = get_bits_count(&s->gb); if (!s->lsf) { _______________________________________________ libav-commits mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-commits
