From 0625a3806628f3abcc6daa87b34ceb0d165b0160 Mon Sep 17 00:00:00 2001 From: Christophe Gisquet Date: Thu, 21 Aug 2014 18:57:18 +0200 Subject: hevc_ps: check overflow and test alternate syntax Some streams were found to have what appeared to be truncated SPS. Their syntax seem to be valid at least until the end of the VUI, so try that syntax if the parsing would overflow the SPS in the conforming syntax. Fixes ticket #3872. Signed-off-by: Michael Niedermayer --- libavcodec/hevc_ps.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) (limited to 'libavcodec') diff --git a/libavcodec/hevc_ps.c b/libavcodec/hevc_ps.c index 2ccce5f78c..29412d27ec 100644 --- a/libavcodec/hevc_ps.c +++ b/libavcodec/hevc_ps.c @@ -471,7 +471,8 @@ static void decode_vui(HEVCContext *s, HEVCSPS *sps) { VUI *vui = &sps->vui; GetBitContext *gb = &s->HEVClc->gb; - int sar_present; + GetBitContext backup; + int sar_present, alt = 1; av_log(s->avctx, AV_LOG_DEBUG, "Decoding VUI\n"); @@ -525,6 +526,10 @@ static void decode_vui(HEVCContext *s, HEVCSPS *sps) vui->frame_field_info_present_flag = get_bits1(gb); vui->default_display_window_flag = get_bits1(gb); + // Backup context in case an alternate header is detected + if( get_bits_left(gb) >= 66) + memcpy(&backup, gb, sizeof(backup)); + if (vui->default_display_window_flag) { //TODO: * 2 is only valid for 420 vui->def_disp_win.left_offset = get_ue_golomb_long(gb) * 2; @@ -552,8 +557,22 @@ static void decode_vui(HEVCContext *s, HEVCSPS *sps) vui->vui_timing_info_present_flag = get_bits1(gb); if (vui->vui_timing_info_present_flag) { + if( get_bits_left(gb) < 66) { + // The alternate syntax seem to have timing info located + // at where def_disp_win is normally located + av_log(s->avctx, AV_LOG_WARNING, + "Strange VUI timing information, retrying...\n"); + vui->default_display_window_flag = 0; + memset(&vui->def_disp_win, 0, sizeof(vui->def_disp_win)); + memcpy(gb, &backup, sizeof(backup)); + alt = 1; + } vui->vui_num_units_in_tick = get_bits_long(gb, 32); vui->vui_time_scale = get_bits_long(gb, 32); + if (alt) { + av_log(s->avctx, AV_LOG_INFO, "Retry got %i/%i fps\n", + vui->vui_time_scale, vui->vui_num_units_in_tick); + } vui->vui_poc_proportional_to_timing_flag = get_bits1(gb); if (vui->vui_poc_proportional_to_timing_flag) vui->vui_num_ticks_poc_diff_one_minus1 = get_ue_golomb_long(gb); -- cgit v1.2.3