[FFmpeg-devel] [PATCH] lavf/vf_deinterlace_vaapi: flush queued frame in field mode

[Linjie Fu]

Add deint_vaapi_request_frame for deinterlace_vaapi, send NULL frame
to flush the queued frame.

Fix the frame drop issue in field mode:

ffmpeg -hwaccel vaapi -vaapi_device /dev/dri/renderD128 -v verbose -c:v
h264 -i ./input.h264 -vf 'format=nv12|vaapi,hwupload,
        deinterlace_vaapi=mode=bob:rate=field,hwdownload,format=nv12'
-pix_fmt yuv420p -f rawvideo -vsync passthrough -y dump.yuv

Signed-off-by: Linjie Fu <linjie.fu at intel.com>
---
 libavfilter/vf_deinterlace_vaapi.c | 46 ++++++++++++++++++++++++++++++++------
 1 file changed, 39 insertions(+), 7 deletions(-)

diff --git a/libavfilter/vf_deinterlace_vaapi.c b/libavfilter/vf_deinterlace_vaapi.c
index 72d0349..c811327 100644
--- a/libavfilter/vf_deinterlace_vaapi.c
+++ b/libavfilter/vf_deinterlace_vaapi.c
@@ -48,6 +48,9 @@ typedef struct DeintVAAPIContext {
     int                queue_count;
     AVFrame           *frame_queue[MAX_REFERENCES];
     int                extra_delay_for_timestamps;
+
+    int                eof;
+    int                prev_pts;
 } DeintVAAPIContext;
 
 static const char *deint_vaapi_mode_name(int mode)
@@ -190,11 +193,16 @@ static int deint_vaapi_filter_frame(AVFilterLink *inlink, AVFrame *input_frame)
     void *filter_params_addr = NULL;
     int err, i, field, current_frame_index;
 
-    av_log(avctx, AV_LOG_DEBUG, "Filter input: %s, %ux%u (%"PRId64").\n",
-           av_get_pix_fmt_name(input_frame->format),
-           input_frame->width, input_frame->height, input_frame->pts);
+    // NULL frame is used to flush the queue in field mode
+    if (input_frame)
+        av_log(avctx, AV_LOG_DEBUG, "Filter input: %s, %ux%u (%"PRId64").\n",
+            av_get_pix_fmt_name(input_frame->format),
+            input_frame->width, input_frame->height, input_frame->pts);
+    else if (ctx->field_rate == 1) {
+        return 0;
+    }
 
-    if (ctx->queue_count < ctx->queue_depth) {
+    if (input_frame && ctx->queue_count < ctx->queue_depth) {
         ctx->frame_queue[ctx->queue_count++] = input_frame;
         if (ctx->queue_count < ctx->queue_depth) {
             // Need more reference surfaces before we can continue.
@@ -291,6 +299,8 @@ static int deint_vaapi_filter_frame(AVFilterLink *inlink, AVFrame *input_frame)
         if (ctx->field_rate == 2) {
             if (field == 0)
                 output_frame->pts = 2 * input_frame->pts;
+            else if (ctx->eof)
+                output_frame->pts = 3 * input_frame->pts - ctx->prev_pts;
             else
                 output_frame->pts = input_frame->pts +
                     ctx->frame_queue[current_frame_index + 1]->pts;
@@ -306,6 +316,8 @@ static int deint_vaapi_filter_frame(AVFilterLink *inlink, AVFrame *input_frame)
             break;
     }
 
+    ctx->prev_pts = input_frame->pts;
+
     return err;
 
 fail:
@@ -315,6 +327,25 @@ fail:
     return err;
 }
 
+static int deint_vaapi_request_frame(AVFilterLink *link)
+{
+    AVFilterContext *avctx = link->src;
+    DeintVAAPIContext *ctx   = avctx->priv;
+    int ret;
+
+    if (ctx->eof)
+        return AVERROR_EOF;
+
+    ret = ff_request_frame(link->src->inputs[0]);
+    if (ret == AVERROR_EOF) {
+        ctx->eof = 1;
+        deint_vaapi_filter_frame(link->src->inputs[0], NULL);
+    } else if (ret < 0)
+        return ret;
+
+    return 0;
+}
+
 static av_cold int deint_vaapi_init(AVFilterContext *avctx)
 {
     VAAPIVPPContext *vpp_ctx = avctx->priv;
@@ -376,9 +407,10 @@ static const AVFilterPad deint_vaapi_inputs[] = {
 
 static const AVFilterPad deint_vaapi_outputs[] = {
     {
-        .name = "default",
-        .type = AVMEDIA_TYPE_VIDEO,
-        .config_props = &deint_vaapi_config_output,
+        .name           = "default",
+        .type           = AVMEDIA_TYPE_VIDEO,
+        .request_frame  = &deint_vaapi_request_frame,
+        .config_props   = &deint_vaapi_config_output,
     },
     { NULL }
 };
-- 
2.7.4