[FFmpeg-devel] [PATCH 4/7] avcodec/dvbsubdec: Support computing clut only once

[Michael Niedermayer]

This avoids crafted files from consuming excessive resources recomputing the clut after each pixel change

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavcodec/dvbsubdec.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/libavcodec/dvbsubdec.c b/libavcodec/dvbsubdec.c
index 9bee33e4a2..6f340460d8 100644
--- a/libavcodec/dvbsubdec.c
+++ b/libavcodec/dvbsubdec.c
@@ -979,7 +979,8 @@ static void dvbsub_parse_pixel_data_block(AVCodecContext *avctx, DVBSubObjectDis
         }
     }
 
-    region->has_computed_clut = 0;
+    if (ctx->compute_clut != -2)
+        region->has_computed_clut = 0;
 }
 
 static int dvbsub_parse_object_segment(AVCodecContext *avctx,
@@ -1737,7 +1738,7 @@ end:
 #define OFFSET(x) offsetof(DVBSubContext, x)
 static const AVOption options[] = {
     {"compute_edt", "compute end of time using pts or timeout", OFFSET(compute_edt), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, DS},
-    {"compute_clut", "compute clut when not available(-1) or always(1) or never(0)", OFFSET(compute_clut), AV_OPT_TYPE_BOOL, {.i64 = -1}, -1, 1, DS},
+    {"compute_clut", "compute clut when not available(-1) or only once (-2) or always(1) or never(0)", OFFSET(compute_clut), AV_OPT_TYPE_BOOL, {.i64 = -1}, -2, 1, DS},
     {"dvb_substream", "", OFFSET(substream), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 63, DS},
     {NULL}
 };
-- 
2.17.1