---
id: "ed25aafa-bb65-4f05-9ca0-d9ec42d82939"
name: "PNG title cards in concat"
micro_summary: "PNG title cards + JPEG frames in one ffmpeg concat fails (\"Invalid PNG signature\") — concat demuxer needs a uniform codec. Fix: render title cards as JPEG."
status: "discarded"
see_also: []
scope: "Probe: use PNG title-card images in the ffmpeg concat list together with the JPEG screencast frames."
discard_reason: "concat demuxer can't mix PNG title cards with JPEG frames (\"Invalid PNG signature\"); fix = render title cards as JPEG."
---
First encode rendered title cards as PNG and fed them into the ffmpeg `concat` demuxer alongside the JPEG screencast frames. ffmpeg errored: `Invalid PNG signature 0xFFD8FFE0...` (0xFFD8 is the JPEG magic) — the concat demuxer needs a single, uniform codec across all inputs and tried to decode JPEG frames with the PNG decoder. Fix: render the title cards as JPEG (`-q:v 2`) so every concat input is MJPEG.