Web audio recorder with playing sync

We request a widget (Javascript+HTML5+CSS + JQUERY if needed) which lets AUDIO recording from a WEB page, when a secondary audio is playing, by using the system microphone or the webcam or the mobile system mic that limits recording to specified seconds and shows a loading bar or slider with the remaining seconds. The UI will show the loading bar/slider unactive and the record button at the start. When user pushes the record button the software will trigger a secondary audio playing (a predefined "mp3" which defines the maximum recording duration) exactly when the real recording starts in user device (after eventual confirm requests by the browser and after eventual latencies due to the device). At this time the bar/slider and counter start to show the remaining recording time. At the end of the recording (it cannot be stopped by the user before the time finishes), this software shows the play button that let the user to listen to the recorded audio, and a "delete" button that reset the software status. This software must calculate the offset (which describes the time of the real hearing of the second "mp3" by the user) with an error less than 5 hundredths of second and will start the loading bar and timing limit at that exact time. This software must let the user to play the previously recorded audio and let to retry if wanted. The software will include a button for sending the recorded audio to a webservice (via HTTP POST or PUT: developer's choice) with the calculated offset between audio playing and audio recording in a further variable of the form (a string, preferably). Developer can use Jquery if needed, or Flash Actionscript 3. Software musts: - to be real crossbrowser (IE 10+, Chrome latest, Firefox latest, Safari latest) and crossplatform (windows Vista+, MacOS 10+, iOS 7+, Android 4.3+). - offset calculus affidability and in sync with the user experience (users will listen to the audio and talk over in sync). This offset should be reliable and with an error less than 5 hundredths of second, or this system will not be useful for our purposes. This software will be embedded in a pre-existing website by the applicant, so it is not required to the developer.