[FFmpeg-devel,2/4] avcodec/qtrle: return last frame even if unchanged

Submitted by Michael Niedermayer on May 30, 2019, 2:03 p.m.

Details

Message ID 20190530140400.6205-2-michael@niedermayer.cc
State New
Headers show

Commit Message

Michael Niedermayer May 30, 2019, 2:03 p.m.
Fixes: Ticket7880

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/qtrle.c        | 42 +++++++++++++++++++++++++++++++++++----
 tests/ref/fate/qtrle-8bit |  1 +
 2 files changed, 39 insertions(+), 4 deletions(-)

Comments

Marton Balint May 31, 2019, 8:28 p.m.
On Thu, 30 May 2019, Michael Niedermayer wrote:

> Fixes: Ticket7880
>
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
> libavcodec/qtrle.c        | 42 +++++++++++++++++++++++++++++++++++----
> tests/ref/fate/qtrle-8bit |  1 +
> 2 files changed, 39 insertions(+), 4 deletions(-)
>
> diff --git a/libavcodec/qtrle.c b/libavcodec/qtrle.c
> index 2c29547e5a..4add1aded6 100644
> --- a/libavcodec/qtrle.c
> +++ b/libavcodec/qtrle.c
> @@ -45,6 +45,8 @@ typedef struct QtrleContext {
>
>     GetByteContext g;
>     uint32_t pal[256];
> +    int need_flush;
> +    AVPacket flush_pkt;
> } QtrleContext;
> 
> #define CHECK_PIXEL_PTR(n)                                                            \
> @@ -444,6 +446,12 @@ 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 +462,32 @@ 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;
> +            s->frame->pkt_pos      = s->flush_pkt.pos;
> +            s->frame->pkt_duration = s->flush_pkt.duration;
> +            s->frame->pkt_dts      = s->flush_pkt.dts;
> +            s->frame->pkt_pts      =
> +            s->frame->pts          = s->flush_pkt.pts;

This does not seem to work, because the magic in decode_simple_internal in 
decode.c will overwrite these fields. Alternative approach which seems to 
work is assigning the AVPacket fields instead:

             avpkt->pos      = s->flush_pkt.pos;
             avpkt->duration = s->flush_pkt.duration;
             avpkt->dts      = s->flush_pkt.dts;
             avpkt->pts      = s->flush_pkt.pts;

Looks a bit ugly, but as far as I see we are using an internal packet, 
and not the one provided by the user, so it might be OK.

Regards,
Marton

Patch hide | download patch | download mbox

diff --git a/libavcodec/qtrle.c b/libavcodec/qtrle.c
index 2c29547e5a..4add1aded6 100644
--- a/libavcodec/qtrle.c
+++ b/libavcodec/qtrle.c
@@ -45,6 +45,8 @@  typedef struct QtrleContext {
 
     GetByteContext g;
     uint32_t pal[256];
+    int need_flush;
+    AVPacket flush_pkt;
 } QtrleContext;
 
 #define CHECK_PIXEL_PTR(n)                                                            \
@@ -444,6 +446,12 @@  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 +462,32 @@  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;
+            s->frame->pkt_pos      = s->flush_pkt.pos;
+            s->frame->pkt_duration = s->flush_pkt.duration;
+            s->frame->pkt_dts      = s->flush_pkt.dts;
+            s->frame->pkt_pts      =
+            s->frame->pts          = s->flush_pkt.pts;
+            if ((ret = av_frame_ref(data, s->frame)) < 0)
+                return ret;
+            *got_frame = 1;
+        }
+        return 0;
+    }
+    s->flush_pkt = *avpkt;
+
     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;
@@ -471,14 +500,18 @@  static int qtrle_decode_frame(AVCodecContext *avctx,
 
     /* if a header is present, fetch additional decoding parameters */
     if (header & 0x0008) {
-        if (avpkt->size < 14)
+        if (avpkt->size < 14) {
+            s->need_flush = 1;
             return avpkt->size;
+        }
         start_line = bytestream2_get_be16(&s->g);
         bytestream2_skip(&s->g, 2);
         height     = bytestream2_get_be16(&s->g);
         bytestream2_skip(&s->g, 2);
-        if (height > s->avctx->height - start_line)
+        if (height > s->avctx->height - start_line) {
+            s->need_flush = 1;
             return avpkt->size;
+        }
     } else {
         start_line = 0;
         height     = s->avctx->height;
@@ -572,5 +605,6 @@  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