[FFmpeg-devel] [PATCH] BugFix #9283: correct setting of key_frame flag in AVFrame using cuviddec on interlaced h264

[stuhlo]

From: stuhlo <stuhlo at gmail.com>

This fixes setting of `key_frame` flag in AVFrame when input h264 packets represents individual fields of interlaced video.
In this case, pairs of two consecutive fields represents a single decoded picture and have identical `CurrPicIdx`, however, only
the first field is entirely intra-coded and has the flag `intra_pic_flag` set and the second field was resetting the flag before
it was even read in the function `cuvid_output_frame`.
---
 libavcodec/cuviddec.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/libavcodec/cuviddec.c b/libavcodec/cuviddec.c
index a5f33e6..f1cc9aa 100644
--- a/libavcodec/cuviddec.c
+++ b/libavcodec/cuviddec.c
@@ -336,7 +336,9 @@ static int CUDAAPI cuvid_handle_picture_decode(void *opaque, CUVIDPICPARAMS* pic
 
     av_log(avctx, AV_LOG_TRACE, "pfnDecodePicture\n");
 
-    ctx->key_frame[picparams->CurrPicIdx] = picparams->intra_pic_flag;
+    if(picparams->intra_pic_flag) {
+        ctx->key_frame[picparams->CurrPicIdx] = picparams->intra_pic_flag;
+    }
 
     ctx->internal_error = CHECK_CU(ctx->cvdl->cuvidDecodePicture(ctx->cudecoder, picparams));
     if (ctx->internal_error < 0)
@@ -593,6 +595,7 @@ static int cuvid_output_frame(AVCodecContext *avctx, AVFrame *frame)
         }
 
         frame->key_frame = ctx->key_frame[parsed_frame.dispinfo.picture_index];
+        ctx->key_frame[parsed_frame.dispinfo.picture_index] = 0;
         frame->width = avctx->width;
         frame->height = avctx->height;
         if (avctx->pkt_timebase.num && avctx->pkt_timebase.den)
-- 
1.8.3.1