ffmpeg: Allow decoding of yuvj420p.

Seems to have worked, although it's not yet clear whether the
full color range is properly processed within the GPU, or if
there is some truncation happening. In any case, the resulting
quality looks Close Enough.

ffmpeg/lpms_ffmpeg.c

@@ -838,7 +838,9 @@ static int open_video_decoder(input_params *params, struct input_ctx *ctx)
       AVCodec *c = avcodec_find_decoder_by_name("h264_cuvid");
       if (c) codec = c;
       else fprintf(stderr, "Cuvid decoder not found; defaulting to software\n");
-      if (AV_PIX_FMT_YUV420P != ic->streams[ctx->vi]->codecpar->format) {
+      if (AV_PIX_FMT_YUV420P != ic->streams[ctx->vi]->codecpar->format &&
+          AV_PIX_FMT_YUVJ420P != ic->streams[ctx->vi]->codecpar->format) {
+        // TODO check whether the color range is truncated if yuvj420p is used
         ret = lpms_ERR_INPUT_PIXFMT;
         dd_err("Non 4:2:0 pixel format detected in input\n");
       }

ffmpeg/nvidia_test.go

@@ -153,6 +153,26 @@ func TestNvidia_Pixfmts(t *testing.T) {
   `
 	run(cmd)
 
+	// Check that yuvj420p is allowed (jpeg color range)
+	// TODO check for color range truncation?
+	cmd = `
+    ffmpeg -loglevel warning -i test.ts -an -c:v libx264 -pix_fmt yuvj420p -t 1 inj420p.mp4
+    ffprobe -loglevel warning inj420p.mp4  -show_streams -select_streams v | grep pix_fmt=yuvj420p
+  `
+	run(cmd)
+	err = Transcode2(&TranscodeOptionsIn{
+		Fname: dir + "/inj420p.mp4",
+		Accel: Nvidia,
+	}, []TranscodeOptions{{
+		Oname:   dir + "/outj420p.mp4",
+		Profile: prof,
+		Accel:   Nvidia,
+	},
+	})
+	if err != nil {
+		t.Error(err)
+	}
+
 	return
 	// Following test vaidates YUV 4:4:4 pixel format encoding which is only supported on limited set of devices for e.g. P100
 	// https://developer.nvidia.com/video-encode-decode-gpu-support-matrix