An intermediate codec will never make your images better

This topic is very important, because it is very commonly misunderstood, and there is a lot of misinformation online. If you have two options for codec at capture, it’s a no-brainer that a better-quality codec will give you better images. Once the images have been captured, however, changing the codec will never make the images better.

Transcoding your footage cannot increase the image quality. There are some extra operations that you could do in the transcode process (such as doing an up-res) that could increase the image quality, but a new codec by itself will never increase the quality of your image.

If you choose the right codec, you can avoid hurting your image, but you can never improve it.

That includes going from H.264 to DNxHD or ProRes. That includes going from 8-bit to 10-bit. That includes going from 4:2:0 to 4:4:4.

Here is an illustration that can help you understand this concept:

This is a photo of a rose reflected in a water droplet. It’s 4 megapixels, and it looks pretty nice on a 27-inch monitor.

Now, what if you take a photo of your monitor with a Red Helium 8k camera? This is a beast of a camera. This photo of the rose was shot with a cheapo Canon Rebel DSLR, worth about $250 today. The Red Helium setup costs about $50,000, it’s 35 megapixels, it’s RAW, it has one of the best camera sensors ever produced.

Which will be a better image – the 4 megapixel photo, or the 35 megapixel photo?

The Red camera has more megapixels, right? It’s raw, and it has all of the Red digital magic, right? But since you’re using a high-resolution camera to take a photo of the photo, not a photo of the rose, your fancy new image will never be better than the first one. You have a file that is technically higher-resolution, but it does not capture any more of the subject (the rose) than the first one did.

This is what you’re doing when you’re transcoding. You are making a copy of a copy, taking a photo of a photo. If you use a fancy high resolution camera to take a photo of a photo, you will be able to preserve pretty much all of the information in the original image, but you won’t be able to add anything more.

The big caveat is that, if you are doing any processing, any transformation of the image (adding a LUT, for instance), then you definitely do want to transcode into a higher-quality codec, which will retain new information. But if you’re not altering the image, then transcoding will not make your image somehow “better.”

To see how different codecs impact image quality, check out the Frame.io Codec Comparison.