v4l2_codec2 encoder: Add support for configuring the bitrate mode.

This CL adds support for the C2_PARAMKEY_BITRATE_MODE parameter to the
v4l2 encoder. This parameter allows configuring the bitrate mode used
to encode a video.

The supported bitrate modes are:
- C2Config::BITRATE_VARIABLE
- C2Config::BITRATE_CONST

Note: Currently the C2 framework does not support configuring the peak
bitrate, which is used when the bitrate mode is set to VBR. Instead we
set the peak bitrate to a multiple of the target bitrate.

Note: Submit after support for V4L2_CID_MPEG_VIDEO_BITRATE_PEAK and
V4L2_CID_MPEG_VIDEO_BITRATE_MODE has been added to the virto encoder in
crrev.com/c/2944506.

BUG: 190336806
BUG: 181514834
Test: arc.VideoEncodeAccel.h264_192p_i420_vm
Change-Id: I95d8f9921c1ba475ea8c65760d3c18e5e2818d5e

1 files changed, 9 insertions, 0 deletions

diff --git a/components/V4L2EncodeInterface.cpp b/components/V4L2EncodeInterface.cpp
index 7f0fb39..2bdf11b 100644
--- a/components/V4L2EncodeInterface.cpp
+++ b/components/V4L2EncodeInterface.cpp
@@ -310,6 +310,15 @@ void V4L2EncodeInterface::Initialize(const C2String& name) {
                          .withSetter(Setter<decltype(*mBitrate)>::StrictValueWithNoDeps)
                          .build());
 
+    addParameter(
+            DefineParam(mBitrateMode, C2_PARAMKEY_BITRATE_MODE)
+                    .withDefault(new C2StreamBitrateModeTuning::output(0u, C2Config::BITRATE_CONST))
+                    .withFields(
+                            {C2F(mBitrateMode, value)
+                                     .oneOf({C2Config::BITRATE_CONST, C2Config::BITRATE_VARIABLE})})
+                    .withSetter(Setter<decltype(*mBitrateMode)>::StrictValueWithNoDeps)
+                    .build());
+
     std::string outputMime;
     if (getCodecFromComponentName(name) == VideoCodec::H264) {
         outputMime = MEDIA_MIMETYPE_VIDEO_AVC;