LectureVideos is a screencast extension to LectureNotes for video and audio recording while taking handwritten notes using LectureNotes.
It has been designed while having a user at university (or at school) in mind, for instance a lecturer who is using it for producing tutorial videos or for recording her/his lecture while teaching using LectureNotes (by writing on the device and projecting the screen content for the audience) or a student who is using it to prepare tutorial videos for fellow students. However, it has many potential applications outside university, for instance in business or technology.
Its major target devices are tablets with Android 4.1 or later (it is developed on a Samsung Galaxy Note 10.1, an Asus Nexus 7, a Samsung Nexus 10, and an Asus MeMO Pad).
NOTE: LectureVideos cannot be used on its own, it is designed to serve as an extension for LectureNotes and can only be used in conjunction with it. If you wish to record video and audio while taking handwritten notes, launch LectureNotes and start video and audio recording there, the video and audio files will be stored within the corresponding notebook directory.
LectureVideos uses the Android MediaCodec API that became available with Android Jelly Bean to encode video and audio, so that Android 4.1 or later is required. It has been carefully tested on a Samsung Galaxy Note 10.1, an Asus Nexus 7, a Samsung Nexus 10, and an Asus MeMO Pad. However, since the behaviors of the Android MediaCodec differ significantly between devices, LectureVideos might not work on a given device.
LectureVideos entirely relies on the Android MediaCodec and does neither contain any codecs nor any other encoding, decoding, multiplexing, or demultiplexing code (mainly to avoid legal problems). The Android MediaCodec APIs of Android 4.1 and 4.2 do not provide a multiplexer to create a container format such as MP4, AVI, or MKV. Therefore, LectureVideos produces two files per session, an H264 file containing the encoded video signal and a 3GP file containing the encoded audio signal.
On devices running Android 4.1 and 4.2, you need an external tool to multiplex the video and audio signals into a container format such as MP4, AVI, or MKV. There are a very large number of tools available on all OS to do that (for instance FFmpeg), and users dealing with video production are very likely to have such tool available anyhow.
On devices running Android 4.3 and 4.4, you can still use an external tool to multiplex the video and audio signals into a container format (which can be advisable if you have specific optimization needs, for instance for streaming); furthermore, you can share the video as an MP4 container file in LectureNotes, and LectureVideos uses the Android MediaCodec API to multiplex the video and audio signals into the MP4 container format prior to sharing.
We would love to hear from you, please send feedback and feature requests to us by email (devel [a] acadoid.com). If you encounter a problem with the app, please email us and we will do our very best to fix it quickly.
* requires only minimal permissions and no internet connection (we do respect your privacy!)
* allows display content and audio signals to be recorded while taking handwritten notes using LectureNotes (root permissions not required)
* allows recorded display content and audio signals to be replayed using LectureNotes
* allows recorded display content and audio signals to be multiplexed into an MP4 container file using LectureNotes (Android 4.3 and 4.4 devices only)
Possible issue: For good audio quality, it is advisable to use an external microphone, in particular when taking notes with a stylus with a hard tip in parallel (the noise that the tip causes on the device display and human voices are in the same frequency range and the former cannot be filtered away reliably).
* optional video/audio time offset added
* more devices supported
* Korean localization added (language of the largest user proportion after English and German, other languages will follow in order of user proportion)
* optional compensation for encoder bug (exchange of chroma components) added
* handling of Android MediaCodec multiplexer improved
* German localization added (language of the largest user proportion after English, other languages will follow in order of user proportion)