vpxdec: support scaling output

Adds an option, --scale, that will rescale any frames produced by
the decoder that don't match the resolution of the first frame to
that resolution. This is useful for playback of files that use
spatial resampling.

Change-Id: I867adc650d535df7ec5b107549359712ea3aaaa0

examples.mk

diff --git a/examples.mk b/examples.mk
index 28430a6..8426ee7 100644
--- a/examples.mk
+++ b/examples.mk
@@ -31,6 +31,7 @@
 vpxdec.SRCS                 += nestegg/halloc/src/macros.h
 vpxdec.SRCS                 += nestegg/include/nestegg/nestegg.h
 vpxdec.SRCS                 += nestegg/src/nestegg.c
+vpxdec.SRCS                 += $(LIBYUV_SRCS)
 vpxdec.GUID                  = BA5FE66F-38DD-E034-F542-B1578C5FB950
 vpxdec.DESCRIPTION           = Full featured decoder
 UTILS-$(CONFIG_ENCODERS)    += vpxenc.c

vpxdec.c

diff --git a/vpxdec.c b/vpxdec.c
index f7281a4..30196ec 100644
--- a/vpxdec.c
+++ b/vpxdec.c
@@ -30,6 +30,7 @@
 #endif
 #include "tools_common.h"
 #include "nestegg/include/nestegg/nestegg.h"
+#include "third_party/libyuv/include/libyuv/scale.h"
 
 #if CONFIG_OS_SUPPORT
 #if defined(_MSC_VER)
@@ -93,6 +94,8 @@
                                             "Show version string");
 static const arg_def_t error_concealment = ARG_DEF(NULL, "error-concealment", 0,
                                                    "Enable decoder error-concealment");
+static const arg_def_t scalearg = ARG_DEF("S", "scale", 0,
+                                            "Scale output frames uniformly");
 
 
 #if CONFIG_MD5
@@ -102,7 +105,7 @@
 static const arg_def_t *all_args[] = {
   &codecarg, &use_yv12, &use_i420, &flipuvarg, &noblitarg,
   &progressarg, &limitarg, &skiparg, &postprocarg, &summaryarg, &outputfile,
-  &threadsarg, &verbosearg,
+  &threadsarg, &verbosearg, &scalearg,
 #if CONFIG_MD5
   &md5arg,
 #endif
@@ -708,6 +711,9 @@
   struct input_ctx        input = {0};
   int                     frames_corrupted = 0;
   int                     dec_flags = 0;
+  int                     do_scale;
+  int                     stream_w = 0, stream_h = 0;
+  vpx_image_t             *scaled_img = NULL;
 
   /* Parse command line */
   exec_name = argv_[0];
@@ -757,6 +763,8 @@
       cfg.threads = arg_parse_uint(&arg);
     else if (arg_match(&arg, &verbosearg, argi))
       quiet = 0;
+    else if (arg_match(&arg, &scalearg, argi))
+      do_scale = 1;
 
 #if CONFIG_VP8_DECODER
     else if (arg_match(&arg, &addnoise_level, argi)) {
@@ -1015,6 +1023,30 @@
       show_progress(frame_in, frame_out, dx_time);
 
     if (!noblit) {
+      if (do_scale) {
+        if (frame_out == 1) {
+          stream_w = img->d_w;
+          stream_h = img->d_h;
+          scaled_img = vpx_img_alloc(NULL, VPX_IMG_FMT_I420,
+                                     stream_w, stream_h, 16);
+        }
+        if (img && (img->d_w != stream_w || img->d_h != stream_h)) {
+          I420Scale(img->planes[VPX_PLANE_Y], img->stride[VPX_PLANE_Y],
+                    img->planes[VPX_PLANE_U], img->stride[VPX_PLANE_U],
+                    img->planes[VPX_PLANE_V], img->stride[VPX_PLANE_V],
+                    img->d_w, img->d_h,
+                    scaled_img->planes[VPX_PLANE_Y],
+                    scaled_img->stride[VPX_PLANE_Y],
+                    scaled_img->planes[VPX_PLANE_U],
+                    scaled_img->stride[VPX_PLANE_U],
+                    scaled_img->planes[VPX_PLANE_V],
+                    scaled_img->stride[VPX_PLANE_V],
+                    stream_w, stream_h,
+                    kFilterBox);
+          img = scaled_img;
+        }
+      }
+
       if (img) {
         unsigned int y;
         char out_fn[PATH_MAX];