Hacker News Reader

Comment by tremon | Hacker News Reader

Sorry, I must be from the previous century... what is a "live photo" and why does it include audio?

Google Pixel has these too, but it calls them Motion Photos. They are formatted as a JPEG with an MP4 appended to it. Kind of a weird format but nice to know that you can recover the video from any motion photo with a clever dd invocation.

Here's my script for the curious:

    #!/bin/bash
    #extract mp4 files from Google Pixel 6 .MP.jpg files
    set -e -u -o pipefail

    extract () {
      dd if="$1" of="$1.mp4" bs=$[$( strings -td "$1" | grep ftypisom | head -n1 | cut -d' ' -f1 ) - 4] skip=1
    }

    for fn in "$@"; do
      extract $fn
    done

How do you get the live pictures from the pixel? All I can do is export as a GIF or mp4. The latter of which also doesn’t include text for me.

I personally use NextCloud to sync all my photos to my home server. You can also copy them using ADB or MTP from your phone. I think you can also send them as a photo with standard android sharing and it will send the video in the concatenated format, though that may depend on the sharing app and settings used.

How does that work without corrupting the jpg for file viewers not expecting it?

Most image viewers ignore bytes after the End Of Image in the jpeg format, so you can stick whatever you want on the end.

In iOS, when you take a photo, by default it actually takes a very short video clip and calls it a "live photo." If you receive a live photo, you can tap and hold on the photo and it will play the video, which sometimes includes audio.

More info: https://support.apple.com/en-us/HT207310

> takes a very short video clip

... _and_ a still photo. You don't lose the full-resolution still photo, and the still photo isn't simply a frame from the video. In case anyone's curious.

Wait isn't the magic here that you do exactly that; choose your still photo from the video - thats what you do with the timeline picker in ios?

In other words the video is exactly the same quality as the photo in each frame so you can pick a moment a second later for example if you film something fast moving.

Does anyone know how it works and isn't gigabytes in size?

Maybe I’ve imagined it but I thought the image quality decreased when selecting a non-default frame.

This is true. Easy verification: hold your phone still and take a photo of a tree at some distance. Go to “key photo” selection scrubber. Zoom in on leaves. Scrub. Observe the quality significantly decreases when not on the preselected position.

The stills captured in video are significantly lower quality than the still image at the heart of a live photo. The few frames of captured video and audio are to provide "live" context, not to let you choose the best shot. It was never intended as a burst capture tool, the iPhone has a separate burst mode by holding down the shutter button that works sort of how you are describing, and will provide a rapid burst of much higher quality stills.

You can change the keyframe on a live photo (ie the image displayed first) from the still capture to a video frame, but I generally would never do this due to the quality drop. It adds a little more memory context to a still photo, its not a burst capture tool.

There are actually some features with live photos I hadn't seen before though that are kind of interesting, for example you can fake a long exposure shot via a feature that interpolates information from the video stills into the main image:

https://osxdaily.com/2018/01/10/take-long-exposure-photos-ip...

One very cool thing about this is that when you snap the photo you actually get a half second or so of video from before you snapped the picture. I've had a number of cases where I fumbled as quick as I could to take a photo, missed the shot, but found that the shot I wanted was in fact captured by the live video.

it's an iOSism for "short video clip"

And by default every photo is a live photo.

Live Photo is much better at telling why you want to use it.

Except it's not. What's the opposite of "live"? "Prerecorded"?

So these Live photos are supposedly not prerecoded - except they actually are. They are a prerecorded video that you send to someone. There is nothing live about it.

You just fell for the marketing.

It’s “live” as in “alive” because you get a bit of motion. The opposite would be “inanimate”, which seems apropos.

You’re right that there’s probably a video format under the hood but the experience to meant to be closer to a still picture with a bit of added magic (a la Harry Potter). The clip is too short to catch much action or have (intentionally) meaningful audio.

Reply on news.ycombinator.com