[FFmpeg-devel] [PATCH v2] avcodec/h2645_vui: Interpret a degenerate SAR as unspecified.

Giovanni Mascellani gmascellani at codeweavers.com
Wed Jul 31 12:45:13 EEST 2024


The specification says that if either the numerator or the
denominator is zero then the SAR is to be intended unspecified.
Internally ffmpeg represents an unspecified SAR as 0/1, while
fractions with a zero denominator are not handled properly;
so we bridge the gap by replacing x/0 with 0/1.

Signed-off-by: Giovanni Mascellani <gmascellani at codeweavers.com>
---
 libavcodec/h2645_vui.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavcodec/h2645_vui.c b/libavcodec/h2645_vui.c
index e5c7bf46f9..c8df733399 100644
--- a/libavcodec/h2645_vui.c
+++ b/libavcodec/h2645_vui.c
@@ -46,6 +46,8 @@ void ff_h2645_decode_common_vui_params(GetBitContext *gb, H2645VUI *vui, void *l
         else if (vui->aspect_ratio_idc == EXTENDED_SAR) {
             vui->sar.num = get_bits(gb, 16);
             vui->sar.den = get_bits(gb, 16);
+            if (vui->sar.den == 0)
+                vui->sar = (AVRational){ 0, 1 };
         } else
             av_log(logctx, AV_LOG_WARNING,
                    "Unknown SAR index: %u.\n", vui->aspect_ratio_idc);
-- 
2.45.2



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