For a long MP4 to be playable within Telegram's internal player, it should ideally meet these standards:

: On some platforms, if an uploaded video exceeds certain internal limits (often around 10–20MB for bots or specific web versions), it may default to showing as a downloadable file rather than a playable media window. 3. Handling Large Uploads

: If you select a video from your gallery on mobile, Telegram typically compresses it to ensure faster playback. This allows the recipient to stream the video immediately without downloading the full file first.