CallinLead iOS developer2022 – 2023
A transcript that follows the audio, word for word.
Callin 2.0 added a transcript to every episode. Tap any word and the audio jumps to just before it. Drag the player and the transcript moves to the word you landed on. I built that on iOS.
Ep 1: The First Hangout!The HangoutWelcome back to the Hangout. Today we’re talking about what it takes to ship an app on your own. Ruben, you did exactly that last year. Walk us through the first week, the part nobody sees.
bufferingProblem
The audio and the transcript had to stay on the same word, whether people tapped the text or dragged the player.
My part
Lead iOS. Playback, the custom scrubber, the transcript view, and the code that kept them in step.
Hard call
The transcript always follows the audio’s current time. Every word knows when it starts, so the right word is always the one the audio just reached.
Result
Tap a word and the audio jumps to it. Drag the player and the transcript follows. The two never disagree.
Every word has a start time
The transcript came with a start time for each word. As the episode plays, the app highlights the word whose start time the audio has just passed.
Tap a word to jump there
Tapping a word moves the audio to just before that word, so you hear it from the start. The highlight then moves because the audio moved, not on its own.
Drag the player to scrub
Drag the scrubber anywhere and the transcript jumps to the word at that point. If the audio pauses to buffer, the highlight waits with it.
Why it held up
There’s only one “now”: the audio’s time. The transcript never keeps its own, so there’s nothing to drift out of sync.
