From 706acb558a38eba633056773280155d66c2f4b24 Mon Sep 17 00:00:00 2001 From: Janne Grunau Date: Fri, 16 Nov 2012 14:31:09 +0100 Subject: [PATCH] h264: enable low delay only if no delayed frames were seen Dropping frames is undesirable but that is the only way by which the decoder could return to low delay mode. Instead emit a warning and continue with delayed frames. Fixes a crash in fuzzed sample nasa-8s2.ts_s20033 caused by a larger than expected has_b_frames value. Low delay keeps getting re-enabled from a presumely broken SPS. CC: libav-stable@libav.org --- libavcodec/h264.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/libavcodec/h264.c b/libavcodec/h264.c index f45c572a41..658d865339 100644 --- a/libavcodec/h264.c +++ b/libavcodec/h264.c @@ -3867,8 +3867,14 @@ again: if (s->flags & CODEC_FLAG_LOW_DELAY || (h->sps.bitstream_restriction_flag && - !h->sps.num_reorder_frames)) - s->low_delay = 1; + !h->sps.num_reorder_frames)) { + if (s->avctx->has_b_frames > 1 || h->delayed_pic[0]) + av_log(avctx, AV_LOG_WARNING, "Delayed frames seen " + "reenabling low delay requires a codec " + "flush.\n"); + else + s->low_delay = 1; + } if (avctx->has_b_frames < 2) avctx->has_b_frames = !s->low_delay;