Battery -powered Raspberry Pi Zero to read and generate SMPTE Timecode

We need to design a battery-powered Raspberry Pi Zero realtime linux system that reads SMPTE timecode [login to view URL] from audio in (when available) and display it on a 7-segment display [login to view URL] - When there is no audio on the input, it generates timecode to audio out using Si5351A board [login to view URL] or a DS3231 RTC [login to view URL] There needs to be a startup loop that reads the audio input for signal, a 4-way switch for type of timecode, checks status of an open/closed circuit, and a push-button for user input. Once the push-button has not been triggered for two seconds and the circuit is open, then the timecode needs to start generating with the hour starting based on number of pushes (1-23) and display it on the 7-segement display. When the circuit is closed, the timecode frame number at that moment is displayed on the 7-segent display for three seconds but will keep generating to the audio out. I already have a Java app that reads it and the adafruit board will be used to generate timecode and play it to the audio out. The system needs to be able to quickly restart upon power loss.