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+# WebRTC APM
+
+APM is the audio processing module of WebRTC project in charge of effects
+like echo cancellation, noise suppression, etc.  The purpose of this
+project is to build a standalone library for Chrome OS system side audio
+processing.
+
+# Files content
+
+* scripts to copy over folders and files from upstream WebRTC project
+  for APM and its dependencies.
+* Copied files from upstream WebRTC project. For example: common_audio,
+  modules, rtc_base and system_wrappers.
+* webrtc_apm.cc/h C wrappers to access APM functions.
+* common-mk based makefiles to build shared library libwebrtc_apm.so
+
+# Update
+
+To update this package to latest upstream WebRC:
+* Run `./script/sync-apm.sh path/to/webrtc-checkout/src .`
+* `emerge webrtc-apm` to see if anything breaks.
+* If emerge success, then we're good.
+* Otherwise look into the emerge failure, and then possibly:
+  * Update sync-apm.sh to copy more files if upstream directory structure changes.
+  * Update makefiles if upstream build files has changed.
+  * Update webrtc-apm ebuild file if dependencies changed.
+* Create a new commit