Add a webrtc{en,de}coderfactory implementation for VideoToolbox

webrtc/sdk/objc/Framework/Classes/videotoolboxvideocodecfactory.cc

+/*
+ *  Copyright 2015 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#include "webrtc/sdk/objc/Framework/Classes/videotoolboxvideocodecfactory.h"
+
+#include "webrtc/base/logging.h"
+#include "webrtc/media/base/codec.h"
+#if defined(WEBRTC_IOS)
+#include "webrtc/sdk/objc/Framework/Classes/h264_video_toolbox_encoder.h"
+#include "webrtc/sdk/objc/Framework/Classes/h264_video_toolbox_decoder.h"
+#endif
+
+// TODO(kthelgason): delete this when CreateVideoDecoder takes
+// a cricket::VideoCodec instead of webrtc::VideoCodecType.
+static const char* NameFromCodecType(webrtc::VideoCodecType type) {

[magjed_webrtc, 2016/11/01 14:00:20]

nit: We should probably move this function to webrtc/media/base/codec.h. I see
the same logic duplicated at least in:
https://cs.chromium.org/chromium/src/third_party/webrtc/modules/video_coding/...
https://cs.chromium.org/chromium/src/third_party/webrtc/modules/video_coding/...
This is fine for now though, and we can fix it in a separate CL.

[kthelgason, 2016/11/01 15:14:31]

Yeah, I agree that it's dirty to be pasting this around, but I was hoping it
would go away quickly with the update of WebRtcVideoDecoderFactory.

+  switch (type) {
+    case webrtc::kVideoCodecVP8:
+      return cricket::kVp8CodecName;
+    case webrtc::kVideoCodecVP9:
+      return cricket::kVp9CodecName;
+    case webrtc::kVideoCodecH264:
+      return cricket::kH264CodecName;
+    default:
+      return "Unknown codec";
+  }
+}
+
+namespace webrtc {
+
+// VideoToolboxVideoEncoderFactory
+
+VideoToolboxVideoEncoderFactory::VideoToolboxVideoEncoderFactory() {
+// Hardware H264 encoding only supported on iOS for now.
+#if defined(WEBRTC_IOS)
+  supported_codecs_.push_back(cricket::VideoCodec("H264"));

[magjed_webrtc, 2016/11/01 14:00:20]

nit: Maybe we should use cricket::kH264CodecName here.

[kthelgason, 2016/11/01 15:14:31]

Done.

+#endif
+}
+
+VideoToolboxVideoEncoderFactory::~VideoToolboxVideoEncoderFactory() {}
+
+VideoEncoder* VideoToolboxVideoEncoderFactory::CreateVideoEncoder(
+    const cricket::VideoCodec& codec) {
+#if defined(WEBRTC_IOS)

[magjed_webrtc, 2016/11/01 14:00:20]

Can we have just one ifdef in the ctor and leave the rest of the code generic,
i.e. not have ifdefs here and in the rest of the functions.

[kthelgason, 2016/11/01 15:14:31]

We could do that, but that requires compiling the files on macOS as well.
There's nothing really wrong with that it just seemed like a bit of a waste.

+  if (IsCodecSupported(supported_codecs_, codec)) {
+    LOG(LS_INFO) << "Creating HW encoder for " << codec.name;
+    return new H264VideoToolboxEncoder();
+  }
+#endif
+  LOG(LS_INFO) << "No HW encoder found for codec " << codec.name;
+  return nullptr;
+}
+
+void VideoToolboxVideoEncoderFactory::DestroyVideoEncoder(
+    VideoEncoder* encoder) {
+#if defined(WEBRTC_IOS)
+  delete encoder;
+  encoder = nullptr;
+#endif
+}
+
+const std::vector<cricket::VideoCodec>&
+VideoToolboxVideoEncoderFactory::supported_codecs() const {
+  return supported_codecs_;
+}
+
+// VideoToolboxVideoDecoderFactory
+
+VideoToolboxVideoDecoderFactory::VideoToolboxVideoDecoderFactory() {
+#if defined(WEBRTC_IOS)
+  supported_codecs_.push_back(cricket::VideoCodec("H264"));
+#endif
+}
+
+VideoToolboxVideoDecoderFactory::~VideoToolboxVideoDecoderFactory() {}
+
+VideoDecoder* VideoToolboxVideoDecoderFactory::CreateVideoDecoder(
+    VideoCodecType type) {
+  const auto codec = cricket::VideoCodec(NameFromCodecType(type));
+#if defined(WEBRTC_IOS)
+  if (IsCodecSupported(supported_codecs_, codec)) {

[magjed_webrtc, 2016/11/01 14:00:20]

Thanks for implementing it like this. I want to replace webrtc::VideoCodecType
with cricket::VideoCodec in the near future, and now we have already prepared
for that.

+    LOG(LS_INFO) << "Creating HW decoder for " << codec.name;
+    return new H264VideoToolboxDecoder();
+  }
+#endif
+  LOG(LS_INFO) << "No HW decoder found for codec " << codec.name;
+  return nullptr;
+}
+
+void VideoToolboxVideoDecoderFactory::DestroyVideoDecoder(
+    VideoDecoder* decoder) {
+#if defined(WEBRTC_IOS)
+  delete decoder;
+  decoder = nullptr;
+#endif
+}
+
+}  // namespace webrtc