Why Files Become Bigger in Emails - Computerphile

To send binary files via a text based system, they'll need encoding. Dr Steve Bagley takes us through the attachment system used in email.

name change, formerly "Why Attachments are Larger in Emails"


This video was filmed and edited by Sean Riley.

[jeromesnail]

I've always wondered what were those equal signs at the end of a base64 encoded string :)

[deeef]

Haha I experienced this exact problem many years ago when attaching a 20 MB file, clearly within the limits of Gmail's 25 MB limit, and it kept getting rejected. Fast-forward hours of debugging, sending myself test e-mails, and analyzing headers... I discovered how grossly antiquated e-mail systems are, even to this day.

[pev_]

Yeah, I remember using uuencode/decode for some things in emails and newsgroups in my university years in the 90's. The Unix email programs did not separate between main text and attachments, so the uuencoded part usually was just seen after the end of the natural language part as a large block of random-looking characters of equal line length :)

[ZedaZ]

I learned how to encode emails last week so that I could write a program to make it easier to attach files when sending emails from our server :D It was so satisfying to send a pdf and have it come out right.

[pasan.]

Engineer - use email for text, ftp for files. User - I will put my cat videos in email thank you!

[martinbean]

I love these videos. Watch for one thing and accidentally learn how the Base 64 algorithm works. Used it for nearly 15 years, but never bothered to look into the algorithm under the hood. Summed up in an easy to understand explanation in seconds in this video!

[EddyGurge]

I could really have used this video some 30 or so years ago! I still really enjoyed it :)

[AlanCanon]

This is a real conundrum. I've generated email attachments programmatically recently enough that I'm not sure I need this trip down memory lane... oh, who am I kidding? [presses play].

[Tiddle_s]

Base64 encoding is 4/3 times (33%) larger. It bothers me that they wouldn't just say you can have attachments up to 20Mb in size but really allow 27Mb (or say you can have 25Mb and allow 34Mb).

[orlovsskibet]

I use Base64 a lot in my daily job, but never cared to find out the details about it, or where it came from. Another nice video - thanks a lot.

[idjles]

I used base64 back in 1989, and I still use it everyday in my job today to push binary via JSON or XML.

[iammaxhailme]

I wish emails would go back to being 78 characters. I'd get a lot more work done if I didn't have to read so much junk.

[Omnifarious]

You need to talk about the matter transport mime type. Also, you have to worry about the email going through some really bizarre re-encodings. Sometimes, for example, email would go through a system that used one of the variants of EBCDIC. And you went on to mention that. 🙂

[MaxDiscere]

So sum up a 18 min video in 2 words: it's base64

[willemvdk]

Then how does Unicode work if mail only supports 7 bit ASCII? Same way? Encoding the UTF16 into Base64 and send the entire message as attachment?

[banananaa]

Could you do a video about the time when napster was used to share software by encoding files into mp3

[_ingoknito]

"don't make eye contact, don't make eye contact ..." 😆

[An.Individual]

5:39 it really looks like he is reading the binary from a sheet in his lap

[BasedPeter]

Phillip Seymour Hoffman still alive and even younger i see!

[olivier]

Cool, I did not know about the = at the end, but I never cared to look either:) Thanks