MJPEG acceleration for video capture using VAAPI

media/filters/jpeg_parser.cc

Index: media/filters/jpeg_parser.cc
diff --git a/media/filters/jpeg_parser.cc b/media/filters/jpeg_parser.cc
index 66a3651210dc1add056c0b11dd71aea572b0f3ea..153ab48c8b3b79d84d349ed89025417599225780 100644
--- a/media/filters/jpeg_parser.cc
+++ b/media/filters/jpeg_parser.cc
@@ -49,6 +49,10 @@ static bool InRange(int value, int a, int b) {
   return a <= value && value <= b;
 }
 
+static int RoundUp(int value, int mul) {
+  return (value + mul - 1) / mul * mul;
+}
+
 // |frame_header| is already initialized to 0 in ParseJpegPicture.
 static bool ParseSOF(const char* buffer,
                      size_t length,
@@ -76,6 +80,8 @@ static bool ParseSOF(const char* buffer,
     return false;
   }
 
+  int max_h_factor = 0;
+  int max_v_factor = 0;
   for (size_t i = 0; i < frame_header->num_components; i++) {
     JpegComponent& component = frame_header->components[i];
     READ_U8_OR_RETURN_FALSE(&component.id);
@@ -89,6 +95,10 @@ static bool ParseSOF(const char* buffer,
     READ_U8_OR_RETURN_FALSE(&hv);
     component.horizontal_sampling_factor = hv / 16;
     component.vertical_sampling_factor = hv % 16;
+    if (component.horizontal_sampling_factor > max_h_factor)
+      max_h_factor = component.horizontal_sampling_factor;
+    if (component.vertical_sampling_factor > max_v_factor)
+      max_v_factor = component.vertical_sampling_factor;
     if (!InRange(component.horizontal_sampling_factor, 1, 4)) {
       DVLOG(1) << "Invalid horizontal sampling factor "
                << static_cast<int>(component.horizontal_sampling_factor);
@@ -102,6 +112,13 @@ static bool ParseSOF(const char* buffer,
     READ_U8_OR_RETURN_FALSE(&component.quantization_table_selector);
   }
 
+  // The size of data unit is 8*8 and the coded size should be extended
+  // to complete minimum coded unit, MCU. See Spec A.2.
+  frame_header->coded_width = RoundUp(frame_header->visible_width,
+                                      max_h_factor * 8);
+  frame_header->coded_height = RoundUp(frame_header->visible_height,
+                                       max_v_factor * 8);
+
   return true;
 }