The last render, and what the platform does to it

What happens after you upload

You upload a file. The platform transcodes it into several versions at different bitrates for different connections. Your viewers never see your file; they see the platform’s re-encode of it.

That single fact determines the whole export strategy. You are not producing a file for viewers, you are producing source material for somebody else’s encoder. Give it good material.

The corollary people get wrong: exporting small to “save upload time” throws away detail before the platform’s encoder has seen it, and the platform then compresses your already-compressed file. Two lossy passes instead of one, and it shows in exactly the places generated footage is already weak: grain, fine texture, gradients in skies.

The settings that matter

• Codec. H.264 is universally compatible and correct for nearly everything. H.265 is more efficient and less universally accepted. Use H.264 unless you have a reason.
• Bitrate. The number that actually decides quality. For 1080p delivery, 15 to 25 Mbps. For 4K, 40 to 60. These are higher than most default presets and they are the single most effective change you can make.
• Profile and level. High profile. Leave the level automatic.
• Audio. AAC at 320kbps stereo. Audio is a small share of the file and there is no reason to economise.
• Frame rate. Whatever the project is. Do not change it at export.
• Colour. Rec.709. Do not export HDR unless somebody specifically asked and can play it back.

# a reliable 1080p master
ffmpeg -i timeline.mov -c:v libx264 -preset slow -crf 16 \
  -pix_fmt yuv420p -c:a aac -b:a 320k master.mp4

yuv420p is not optional for wide compatibility. A file exported in 4:4:4 or 4:2:2 will refuse to play on a surprising number of devices and platforms, and it is a common and confusing delivery failure.

Grain and bitrate interact

Worth its own note because it bites people who just learned about grain. Grain is high-frequency detail and it is the first thing a codec discards. Heavy grain at a low bitrate produces a smeared, blocky mess where the grain used to be.

So: keep the grain light, keep the bitrate up, and check your export at full size before delivering. If the grain has turned to mush, either raise the bitrate or reduce the grain.

Platform specifications

Vertical platforms want 1080×1920, 30fps, and they overlay interface on the lower portion. YouTube accepts almost anything and prefers higher bitrates than its own guidance suggests. Broadcast wants exactly what the broadcaster’s spec document says and will reject anything else.

Two habits:

• Read the current spec before delivering, because they change and a two-year-old blog post is not a spec.
• Export a master first, at high bitrate in your project’s native format, and derive platform versions from it. Never export a platform version as your only copy: it is already compressed for somebody else’s pipeline and it cannot be un-compressed.

Two exports, always

Keep a master and deliver a copy. The master is high bitrate, full resolution, no platform-specific cropping, no burned-in subtitles. It is what you go back to when the client wants a square version or a different edit.

File it with the project, with the date in the name.

The delivery checklist

Before anything leaves your machine:

• Every clip trimmed of its settle and its drift.
• One grade and one grain pass across the whole timeline, not per clip.
• Frame rate conformed; upscaled once at the end, if at all.
• Real sound under every shot, with no moment of true digital silence.
• Levels checked: dialogue around -12dB to -6dB peak, music well below it.
• A visible label on generated content, at the start, in frame.
• Written consent on file for any real face or voice, specific to this use.
• Licences filed for every piece of music and every font.
• The prompt, seed, first frame and model version saved beside the project for every shot that shipped.
• Watched once, end to end, on a phone.

Today: export your current project at your editor’s default preset and again at 20 Mbps, and compare the two at full size on the busiest shot.