H.264 video codec support using OpenH264/FFmpeg

webrtc/modules/video_coding/codecs/h264/h264.cc

 /*
  *  Copyright (c) 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/modules/video_coding/codecs/h264/include/h264.h"
 
+#if defined(WEBRTC_OPENH264)
+#include "webrtc/modules/video_coding/codecs/h264/h264_encoder_impl.h"
+#include "webrtc/modules/video_coding/codecs/h264/h264_decoder_impl.h"
+#endif
 #if defined(WEBRTC_IOS)
 #include "webrtc/modules/video_coding/codecs/h264/h264_video_toolbox_decoder.h"
 #include "webrtc/modules/video_coding/codecs/h264/h264_video_toolbox_encoder.h"
 #endif
 
 #include "webrtc/base/checks.h"
 
 namespace webrtc {
 
 // We need this file to be C++ only so it will compile properly for all
 // platforms. In order to write ObjC specific implementations we use private
 // externs. This function is defined in h264.mm.
 #if defined(WEBRTC_IOS)
 extern bool IsH264CodecSupportedObjC();
 #endif
 
+// If any H.264 codec is supported (iOS HW or OpenH264).
 bool IsH264CodecSupported() {
 #if defined(WEBRTC_IOS)
-  return IsH264CodecSupportedObjC();
+  if (IsH264CodecSupportedObjC()) {
+    return true;
+  }
+#endif
+#if defined(WEBRTC_OPENH264)
+  return true;
 #else
   return false;
 #endif
+}
+
+// If H.264 codec is supported and OpenH264 is the implementation used, meaning
+// H264EncoderImpl and H264DecoderImpl.
+bool IsOpenH264CodecSupported() {
+#if defined(WEBRTC_OPENH264)
+  #if defined(WEBRTC_IOS)
+    // If on iOS and we have HW H.264 support we will prefer that over OpenH264
+    // and say that OpenH264 is not supported (even though some H264 is).
+    // TODO(hbos): If we could support both HW and SW implementations then we
+    // should do so and have the ability to choose.
+    return !IsH264CodecSupportedObjC();
+  #else
+    return true;
+  #endif
+#else
+  return false;
+#endif
 }
 
 H264Encoder* H264Encoder::Create() {
   RTC_DCHECK(H264Encoder::IsSupported());
 #if defined(WEBRTC_IOS) && defined(WEBRTC_VIDEO_TOOLBOX_SUPPORTED)
-  return new H264VideoToolboxEncoder();
-#else
+  if (IsH264CodecSupportedObjC()) {
+    return new H264VideoToolboxEncoder();
+  }
+#endif
+#if defined(WEBRTC_OPENH264)
+  if (IsOpenH264CodecSupported()) {
+    return new H264EncoderImpl();
+  }
+#endif
   RTC_NOTREACHED();
   return nullptr;
-#endif
 }
 
 bool H264Encoder::IsSupported() {
   return IsH264CodecSupported();
 }
 
+bool H264Encoder::IsSupportedOpenH264() {
+  return IsOpenH264CodecSupported();
+}
+
 H264Decoder* H264Decoder::Create() {
   RTC_DCHECK(H264Decoder::IsSupported());
 #if defined(WEBRTC_IOS) && defined(WEBRTC_VIDEO_TOOLBOX_SUPPORTED)
-  return new H264VideoToolboxDecoder();
-#else
+  if (IsH264CodecSupportedObjC()) {
+    return new H264VideoToolboxDecoder();
+  }
+#endif
+#if defined(WEBRTC_OPENH264)
+  if (IsOpenH264CodecSupported()) {
+    return new H264DecoderImpl();
+  }
+#endif
   RTC_NOTREACHED();
   return nullptr;
-#endif
 }
 
 bool H264Decoder::IsSupported() {
   return IsH264CodecSupported();
 }
 
+bool H264Decoder::IsSupportedOpenH264() {
+  return IsOpenH264CodecSupported();
+}
+
 }  // namespace webrtc