media too large

[rillian]

I tried sharing a photo from the Firefox OS gallery app, but the post fails with

Error: one or more of the uploaded media is too large.

This is on a Sony Z3c, so it's a 4.4 MB 3936x5248 pixel image.

Doesn't happen with the twitter.com website it with the twidere android client on the same hardware.

Does twitter require downsampling the image?

[rillian]

"Media uploads for images are limited to 5MB in file size, and for videos are limited to 15MB. For chunked uploads, the maximum chunk size is 5MB." -- https://dev.twitter.com/rest/reference/post/media/upload

So macaw might be over the limit if it's sending base64 media_data.

[minego]

The wording of
https://dev.twitter.com/rest/reference/post/media/upload-chunked implies
that even a chunked image has a total maximum size of 5MB. I'm not sure
if I am reading that correctly though.

On 08/19/15 15:50, Ralph Giles wrote:

"Media uploads for images are limited to 5MB in file size, and for
videos are limited to 15MB. For chunked uploads, the maximum chunk size
is 5MB." -- https://dev.twitter.com/rest/reference/post/media/upload

So macaw might be over the limit if it's sending base64 |media_data| and
not chunking.

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[rillian]

Yes, I think you're right. Presumedly that's per-image. Maybe 5MB < 4.4MB because of inconsistent units?

[minego]

On 08/19/15 15:57, Ralph Giles wrote:

Yes, I think you're right. Presumedly that's per-image. Maybe 5MB <
4.4MB because of inconsistent units?

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That seems likely to me.

I suspect that twitter wants the client to resize the image before
sending it. I'm not sure how I can do that in this case. This may take
some experimentation.

[rillian]

I suppose you can draw it into a hidden canvas element? How does the thumbnailing work?

https://hacks.mozilla.org/2011/01/how-to-develop-a-html5-image-uploader/

canvas.toBlob() looks like the most efficient interface for getting the new jpeg data for upload.
https://developer.mozilla.org/en-US/docs/Web/API/HTMLCanvasElement/toBlob

[minego]

That is basically what the thumbnail does. That is a possibility but it
doesn't give me a great deal of control over the final size.
On Aug 20, 2015 7:53 AM, "Ralph Giles" notifications@github.com wrote:

I suppose you can draw it into a hidden canvas element? How does the
thumbnailing work?

https://hacks.mozilla.org/2011/01/how-to-develop-a-html5-image-uploader/

canvas.toBlob() looks like the most efficient interface for getting the
new jpeg data for upload.
https://developer.mozilla.org/en-US/docs/Web/API/HTMLCanvasElement/toBlob

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[rillian]

Media in my timeline on the website is all scaled to 600px width. So if you downsample to 1280 (or even 1920) as a maximum dimension it should be considerably smaller that 5MB as a jpeg and still display with reasonable quality.

Maybe do a loop to explore a few options. Try converting png to png, jpeg to jpeg. If the result is too large (Blob.size) try again with a lower jpeg quality, or with jpeg instead of png, or halve the dimensions.