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Glossary

Aspect Ratio

Also known as: 16:9, 9:16, 1:1

Aspect ratio shapes the entire visual language of a platform. TikTok and Reels use 9:16 because phones are held vertically — the video fills the entire screen with no black bars. YouTube traditionally used 16:9 because TVs and monitors are horizontal, but YouTube Shorts shifted to 9:16 to compete with TikTok. Square (1:1) was Instagram's signature for years because it was a compromise between vertical and horizontal that worked on any device orientation.

The practical issue with mixing aspect ratios: a 9:16 vertical TikTok played on a 16:9 horizontal YouTube layout shows huge black bars on the sides. Conversely, a 16:9 video cropped to 9:16 loses content from the sides. There is no perfect cross-platform aspect ratio — creators who want to be everywhere typically shoot 9:16 (because that has the strongest growth tailwind) and accept the bars on horizontal platforms.

When you download a video, you get the original aspect ratio the platform stored. DropZap doesn't crop or letterbox; the file you download has the same shape as the source. If you need to change aspect ratio after downloading (e.g. to repost a TikTok on YouTube without bars), you'd need a video editor or FFmpeg's crop/pad filters.

Related terms

1080p
1080p is a video resolution of 1920×1080 pixels (1920 wide by 1080 tall) — also called Full HD. The 'p' stands for progressive scan, meaning every frame is rendered as a complete image rather than interlaced. 1080p is the maximum resolution at which TikTok, Instagram, Twitter / X, and Facebook serve video.
H.264
H.264 (also called AVC, Advanced Video Coding) is the most widely used video compression codec on the internet. It compresses raw video into a much smaller file while preserving high visual quality, and it is the codec inside virtually every MP4 file served by TikTok, Instagram, YouTube, Facebook, X / Twitter, and Reddit.
MP4
MP4 (MPEG-4 Part 14) is a digital container format that holds video, audio, subtitles, and metadata in a single file. It is the dominant video format on the modern internet — TikTok, Instagram, YouTube, X / Twitter, Facebook, and Reddit all serve videos as MP4 internally.