V4L2SVD: Allocate video frame with frame size adjusted by a video driver

The alignment to width and height is changed by codec. The v4l2 driver returns
a width and height with taking into that account. On the other hand, gbm doesn't
know about codec in the allocation. This causes gbm allocates a smaller or
larger buffer than a video driver expects. A small buffer is defintely problem.
A larger buffer is problem if a v4l2 pixel format is single planar. If there is
an extra data between planes unexpected by a driver, the driver reads the next
plane from the wrong position because we cannot specify offset for each plane
with a single planar pixel format. This CL resolves this issue by asking minigbm
to allocate a buffer with width and size already adjusted by a video driver.

Bug: 979115
Test: video_decode_accelerator_tests on kevin
Change-Id: Ibe865530547055256015f9e734e31cd5ed6fbd0f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1730910
Commit-Queue: Hirokazu Honda <hiroh@chromium.org>
Reviewed-by: Chih-Yu Huang <akahuang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683899}

media/gpu/v4l2/v4l2_slice_video_decoder.cc

@@ -426,8 +426,8 @@ bool V4L2SliceVideoDecoder::SetupInputFormat(uint32_t input_format_fourcc) {
 }
 
 base::Optional<struct v4l2_format>
-V4L2SliceVideoDecoder::SetFormatOnOutputQueue(uint32_t format_fourcc,
-                                              const gfx::Size& size) {
+V4L2SliceVideoDecoder::SetV4L2FormatOnOutputQueue(uint32_t format_fourcc,
+                                                  const gfx::Size& size) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(decoder_sequence_checker_);
 
   struct v4l2_format format = {};
@@ -457,19 +457,26 @@ base::Optional<VideoFrameLayout> V4L2SliceVideoDecoder::SetupOutputFormat(
     if (!device_->CanCreateEGLImageFrom(format_fourcc))
       continue;
 
+    base::Optional<struct v4l2_format> format =
+        SetV4L2FormatOnOutputQueue(format_fourcc, size);
+    if (!format)
+      continue;
+
+    // S_FMT is successful. Next make sure VFPool can allocate video frames with
+    // width and height adjusted by a video driver.
+    gfx::Size adjusted_size(format->fmt.pix_mp.width,
+                            format->fmt.pix_mp.height);
+
     // Make sure VFPool can allocate video frames with width and height.
     auto frame_layout =
-        UpdateVideoFramePoolFormat(format_fourcc, size, visible_rect);
-    if (!frame_layout) {
-      continue;
-    }
+        UpdateVideoFramePoolFormat(format_fourcc, adjusted_size, visible_rect);
+    if (frame_layout) {
+      if (frame_layout->coded_size() != adjusted_size) {
+        VLOGF(1) << "The size adjusted by VFPool is different from one "
+                 << "adjusted by a video driver";
+        continue;
+      }
 
-    // Next S_FMT with the size adjusted by VFPool.
-    gfx::Size adjusted_size(frame_layout->planes()[0].stride,
-                            frame_layout->coded_size().height());
-    base::Optional<struct v4l2_format> format =
-        SetFormatOnOutputQueue(format_fourcc, adjusted_size);
-    if (format) {
       num_output_planes_ = format->fmt.pix_mp.num_planes;
       return frame_layout;
     }

media/gpu/v4l2/v4l2_slice_video_decoder.h

@@ -143,7 +143,7 @@ class MEDIA_GPU_EXPORT V4L2SliceVideoDecoder : public VideoDecoder,
   // Call VIDIOC_S_FMT with |format_fourcc| and |size|. Returns v4l2_format
   // returned by VIDIOC_S_FMT on success, otherwise returns base::nullopt.
   // This should be called only from SetupOutputFormat().
-  base::Optional<struct v4l2_format> SetFormatOnOutputQueue(
+  base::Optional<struct v4l2_format> SetV4L2FormatOnOutputQueue(
       uint32_t format_fourcc,
       const gfx::Size& size);
   // Setup format for output queue. This function sets output format on output