https://www.reddit.com/r/ProgrammerHumor/comments/69j851/css/dh70f74/

The bot doesn't seem to have learned human phrasing as of yet.

Example: This mp4 version is 1.96 times smaller than the gif (25.54 MB vs 13.06 MB).

While this is nice in that it has no corner cases, a human would likely phrase this as 'This mp4 is 1/2 the size of the gif (25.54 MB vs 13.06 MB).

(Consider rounding to the nearest integer divisor and rephrasing the reply text)

no message.

How much gif would a gifv host if a giphy could host gif

nobutreally though, this post's gifv was unnecessarily re-encoded, going from a 1.1MiB file to a 2.3MiB file.

I see there's a very recent commit that addresses giphy, but I figured I'd bring this up anyway since the post in question happened afterward. Maybe the new version just wasn't deployed yet though, I haven't followed this bot enough.

First example I stumbled across of this bot had inflated the size of a gif by 22% (396,832 to 487,337 bytes), maybe do a check?

As it stands, your bot is unable to tell GIF images from GIF animations. This unnecessarily creates single-frame mp4 files from static images.

The following Javascript code accepts a binary string as an argument. It returns true if it's a multi-frame GIF, false on a single-frame GIF, undefined if there's an error. Yes, this is the skeleton of a GIF block decoder, straight from the spec.

Of course, it requires your bot to actually fetch the images from remote servers. I have no experience with Node.js, so I don't know if this is practical, but you may want to make an HTTP HEAD request before fetching the image, in order to avoid 404 errors and also because GIFs larger than 1 MB are most likely animations anyway.

function isAnimatedGIF(binaryData)
{
    var offset = 13;
    var layerCount = 0;
    function readblocks()
    {
        var bs = binaryData.charCodeAt(offset) & 0xff;
        while(bs != 0) {
            offset += bs + 1;
            bs = binaryData.charCodeAt(offset) & 0xff;
        }
        offset++;
    }
    if(binaryData.substring(0, 3) != 'GIF') {
        return undefined;
    }
    var lsd = binaryData.charCodeAt(10) & 0xff;
    if(lsd & 128) {
        // Global palette
        offset += 3 * ( 1 << ( ( lsd & 7 ) + 1 ) );
    }
    while(offset < binaryData.length) {
        var blockType = binaryData.charCodeAt(offset) & 0xff;
        if(blockType == 0x3b) {
            // End of stream
            break;
        }
        if(blockType == 0x21) {
            // Extension block
            offset += 2;
            readblocks();
            continue;
        }
        if(blockType == 0x2C) {
            // Image description block
            layerCount++;
            var lsd = binaryData.charCodeAt(offset + 9) & 0xff;
            offset += 11;
            if(lsd & 128) {
                // Local palette
                offset += 3 * ( 1 << ( ( lsd & 7 ) + 1 ) );
            }
            readblocks();
            continue;
        }
        return undefined;
    }
    return layerCount > 1;
}

At https://www.reddit.com/r/TenYearsAgoOnReddit/comments/68hkpc/20070501_doonesbury_predicts_outcome_of_iraq_war/.compact the bot replaced a non-animated GIF.

For example here the MP4 is larger than the GIF, making the text that "mp4s have a drastically smaller file size than gifs" look really silly.

There is no license included with the source, so it's licensing status is unknown. Please add some sort of license :)

https://www.reddit.com/r/blackmagicfuckery/comments/7cse4c/the_underwater_view/dpsaci6/

This mp4 version is 97.08% smaller than the gif (845.87 KB vs 28.31 MB).

The mp4 is ~3x smaller.

https://www.reddit.com/r/TheSimpsons/comments/6qam8l/im_the_first_nonbrazilian_person_to_travel/dkvsli8