Move list of supported H264 codecs from InternalEncoderFactory to h264.h

This CL is a clean-up to prepare for adding more supported codecs for the internal H264 SW codec.

Bug: webrtc:8317
Change-Id: If483d05c01c40bbc81cbd1a6aad89961689714ef
Reviewed-on: https://webrtc-review.googlesource.com/4940
Reviewed-by: Sami Kalliomäki <sakal@webrtc.org>
Reviewed-by: Rasmus Brandt <brandtr@webrtc.org>
Commit-Queue: Magnus Jedvert <magjed@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20105}

modules/video_coding/BUILD.gn

@@ -188,6 +188,7 @@ rtc_static_library("webrtc_h264") {
   defines = []
   deps = [
     ":video_coding_utility",
+    "../../api/video_codecs:video_codecs_api",
     "../../media:rtc_media_base",
     "../../rtc_base:rtc_base_approved",
     "../../system_wrappers",

modules/video_coding/codecs/h264/h264.cc

@@ -11,6 +11,8 @@
 
 #include "modules/video_coding/codecs/h264/include/h264.h"
 
+#include "api/video_codecs/sdp_video_format.h"
+
 #if defined(WEBRTC_USE_H264)
 #include "modules/video_coding/codecs/h264/h264_decoder_impl.h"
 #include "modules/video_coding/codecs/h264/h264_encoder_impl.h"
@@ -27,6 +29,15 @@ namespace {
 bool g_rtc_use_h264 = true;
 #endif
 
+// If any H.264 codec is supported (iOS HW or OpenH264/FFmpeg).
+bool IsH264CodecSupported() {
+#if defined(WEBRTC_USE_H264)
+  return g_rtc_use_h264;
+#else
+  return false;
+#endif
+}
+
 }  // namespace
 
 void DisableRtcUseH264() {
@@ -35,13 +46,18 @@ void DisableRtcUseH264() {
 #endif
 }
 
-// If any H.264 codec is supported (iOS HW or OpenH264/FFmpeg).
-bool IsH264CodecSupported() {
-#if defined(WEBRTC_USE_H264)
-  return g_rtc_use_h264;
-#else
-  return false;
-#endif
+std::vector<SdpVideoFormat> SupportedH264Codecs() {
+  if (!IsH264CodecSupported())
+    return std::vector<SdpVideoFormat>();
+  std::vector<SdpVideoFormat> codecs;
+
+  codecs.push_back(SdpVideoFormat(
+      cricket::kH264CodecName, {{cricket::kH264FmtpProfileLevelId,
+                                 cricket::kH264ProfileLevelConstrainedBaseline},
+                                {cricket::kH264FmtpLevelAsymmetryAllowed, "1"},
+                                {cricket::kH264FmtpPacketizationMode, "1"}}));
+
+  return codecs;
 }
 
 H264Encoder* H264Encoder::Create(const cricket::VideoCodec& codec) {

modules/video_coding/codecs/h264/include/h264.h

@@ -12,17 +12,25 @@
 #ifndef MODULES_VIDEO_CODING_CODECS_H264_INCLUDE_H264_H_
 #define MODULES_VIDEO_CODING_CODECS_H264_INCLUDE_H264_H_
 
+#include <vector>
+
 #include "media/base/codec.h"
 #include "modules/video_coding/include/video_codec_interface.h"
 
 namespace webrtc {
 
+struct SdpVideoFormat;
+
 // Set to disable the H.264 encoder/decoder implementations that are provided if
 // |rtc_use_h264| build flag is true (if false, this function does nothing).
 // This function should only be called before or during WebRTC initialization
 // and is not thread-safe.
 void DisableRtcUseH264();
 
+// Returns a vector with all supported internal H264 profiles that we can
+// negotiate in SDP, in order of preference.
+std::vector<SdpVideoFormat> SupportedH264Codecs();
+
 class H264Encoder : public VideoEncoder {
  public:
   static H264Encoder* Create(const cricket::VideoCodec& codec);