[FFmpeg-devel] [PATCH] avcodec/qtrle: return last frame even if unchanged

[Michael Niedermayer]

Fixes: Ticket7880

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavcodec/qtrle.c        | 27 +++++++++++++++++++++++++--
 tests/ref/fate/qtrle-8bit |  1 +
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/libavcodec/qtrle.c b/libavcodec/qtrle.c
index 2c29547e5a..11226cb842 100644
--- a/libavcodec/qtrle.c
+++ b/libavcodec/qtrle.c
@@ -45,6 +45,7 @@ typedef struct QtrleContext {
 
     GetByteContext g;
     uint32_t pal[256];
+    int need_flush;
 } QtrleContext;
 
 #define CHECK_PIXEL_PTR(n)                                                            \
@@ -444,6 +445,12 @@ static av_cold int qtrle_decode_init(AVCodecContext *avctx)
     return 0;
 }
 
+static void qtrle_flush(AVCodecContext *avctx){
+    QtrleContext *s = avctx->priv_data;
+
+    s->need_flush = 0;
+}
+
 static int qtrle_decode_frame(AVCodecContext *avctx,
                               void *data, int *got_frame,
                               AVPacket *avpkt)
@@ -454,11 +461,26 @@ static int qtrle_decode_frame(AVCodecContext *avctx,
     int has_palette = 0;
     int ret, size;
 
+    if (!avpkt->data) {
+        if (s->need_flush) {
+            s->need_flush = 0;
+            if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)
+                return ret;
+            if ((ret = av_frame_ref(data, s->frame)) < 0)
+                return ret;
+            *got_frame = 1;
+        }
+        return 0;
+    }
+
     bytestream2_init(&s->g, avpkt->data, avpkt->size);
 
     /* check if this frame is even supposed to change */
-    if (avpkt->size < 8)
+    if (avpkt->size < 8) {
+        s->need_flush = 1;
         return avpkt->size;
+    }
+    s->need_flush = 0;
 
     /* start after the chunk size */
     size = bytestream2_get_be32(&s->g) & 0x3FFFFFFF;
@@ -572,5 +594,6 @@ AVCodec ff_qtrle_decoder = {
     .init           = qtrle_decode_init,
     .close          = qtrle_decode_end,
     .decode         = qtrle_decode_frame,
-    .capabilities   = AV_CODEC_CAP_DR1,
+    .flush          = qtrle_flush,
+    .capabilities   = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY,
 };
diff --git a/tests/ref/fate/qtrle-8bit b/tests/ref/fate/qtrle-8bit
index 27bb8aad71..39a03b7b6c 100644
--- a/tests/ref/fate/qtrle-8bit
+++ b/tests/ref/fate/qtrle-8bit
@@ -61,3 +61,4 @@
 0,        160,        160,        1,   921600, 0xcfd6ad2b
 0,        163,        163,        1,   921600, 0x3b372379
 0,        165,        165,        1,   921600, 0x36f245f5
+0,        166,        166,        1,   921600, 0x36f245f5
-- 
2.21.0