Compressing video for a store without ruining it

A product video has a different job from a film, and the encoding decisions that suit one are wrong for the other. The goal is not the best possible image; it is the best image that arrives before the shopper loses interest.

Resolution: less than you think

A card in a three-across grid on a desktop is around 400 pixels wide. On a phone it might be 350. Serving 4K into that is spending bandwidth on detail the display cannot show.

1080p is ample for a full-screen phone player. 720p is genuinely fine for cards. The difference in file size between 4K and 1080p is large; the difference a shopper can see, at card size, is none.

Several versions, chosen per device

The better approach than picking one compromise is to encode a few — say 480p, 720p and 1080p — and let the right one be served based on the device and the connection. A phone on a weak signal gets the light version and the page stays usable; a desktop on fibre gets the full one.

This matters most for the shoppers you hear from least. Someone on a poor connection does not email to say the video was slow; they leave.

Bitrate is where the quality actually lives

Resolution gets the attention and bitrate does the work. A well-encoded 720p file looks better than a starved 1080p one, and is smaller.

Variable bitrate is worth using: it spends data on the complicated moments — motion, texture, a pan across fabric — and saves it on the still ones. Most product video is mostly still, so the saving is substantial.

Length is the biggest lever

Worth saying plainly: cutting a video from forty seconds to fifteen removes more bytes than any encoding setting will. And, as it happens, the fifteen-second version usually performs better anyway.

If a video is too heavy, trim it before you compress it harder. Quality lost to over-compression is visible; a scene the shopper never needed is not missed.

Practical starting points

• Card video: 720p, short, clean loop.
• Full-screen player: 1080p, up to about 30 seconds.
• Audio: keep it, but do not rely on it — everything autoplays muted. Where a video has no meaningful sound, dropping the audio track saves real bytes.
• Aspect ratio: vertical, 9:16, for anything that will be a card or a full-screen player. Horizontal video in a vertical slot means letterboxing, and letterboxing at card size means a small video in a large black box.

What not to do

Do not re-encode something that is already compressed if you can avoid it. Exporting a downloaded social video through another compressor stacks two rounds of loss and produces the blocky, smeared look that reads instantly as reposted content. Import the original where you can.