Media size and format

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What media formats should you use and how large should your media files be? In this interview Reece Lamshed asks John Parnell Pierce to explain the best approach for adding media to a website.

MP3 compression settings in audacity.

Keypoints

  • media files are much larger
  • think in terms of bandwidth not file size
  • when compressing, set the media’s bandwidth to match your intended users internet connection
  • there is no one single standard. You may need to pick the playback technology to match your audience

Note: This interview is 6 years old.  It was part of a training resource for beginner interactive media students. Though web technology has changed, the principles discussed are still relevant.

Transcript

REECE: When we move to say audio or video and animation, even though there are ways of compressing that file to make it smaller and better for running on a lower line connection or modem or whatever. We’re still talking about relatively large files.

JOHN: When you’re working with the audio and video and even technologies like Flash, I tend to actually think more in terms of bandwidth, and I limit it. One big advantages of using these formats is they do what’s known as streaming, and it is that as file loads it can actually  be playing at same time.

I will try to keep my audio and video files within the given bandwidth, for example, 128 kilobits per seconds is pretty much standard for MP3’s now. You know that’s sort of equivalent to FM radio quality. You can go to 256 kilobits for seconds which is sort of closed to CD quality. If you used those bandwidths, most broadband users will be able to stream that audio in real time, and likewise with video. And with video you might look at, and you can go down to the sort of, 120 kilobits per second but 256 and 512 are much better quality. Part of it depends on how you size the video. What is the size that you are looking at…

But you don’t want to go for high bandwidth, the reality is that raw video itself is in the megabytes per second.

REECE: It’s just unattainable.

JOHN: Yeah. Until we have sort of high speed fibre optic systems and things, we wont be working with that sort of level, but at the same time the compression technologies are getting really good. You know, mp3 did the most amazing thing for audio because the quality is really outstanding at very very low bandwidths.

REECE: Normally, with MP3 you are talking about an hour of content for 25 megabytes, I mean it’s amazing really, how well that can be compressed.

JOHN: That is right. And if you consider 70 minutes of audio is a full CD, which is about 640 megabytes, so there’s a reduction there, it’s a  large factor.

REECE: Where’s with video you can’t get to that level. I just talked about the insertion of perhaps audio in to a web page. I mean there are different ways of doing that, do you favour, other than trying to stream, but for us, we are building a little simple website, we don’t necessary have that facility.

JOHN: With any of the multimedia contents, you find there multiple ways to do things. Part of it is limited by the formats that are available and the different players that are out there, and then also by the browser technology. You can view or listen to that audio and video by either using a plug-in which is built into the browser or by linking directly to the content. If you link to the content you then have to make sure your computer has the appropriate player on it, and your user has the appropriate player. If you’re going to do this as a plug-in by either embedding the audio as audio or using an OBJECT tag. Programs like Dreamweaver and Flash will actually do this stuff for you. So if you’re building a Flash movie, when you publish it, it will actually create the code to display the Flash within a web page and Dreamweaver will allow you to embed the audio into the appropriate place… and the video.

Part of it is determining your format. With video at the moment you got Windows Media, you got of QuickTime, you got Real Media, we also use Divx which is effective in MPEG-4, that you can used MPEG-4 and you can use MPEG. There is quite a broad range standards. You can actually do Flash video. Flash video is becoming very popular because flash has a very high penetration of a computers, and if you publish a file video it means 80 percent of users are going to be able to view your video. Where as you can do it in QuickTime, it’s going be limited to Mac users and PC users that installed QuickTime on the computer. Real media is sort of fading out a popularity because of its propriety system that you have to install it

REECE: And then you have to pay for it.

JOHN: Likewise, with audio, you can do MP3, MP3 has become very popular distribution format. However, you can also do Windows Media Audio, likewise QuickTime again handles audio. You can embed MP3 in to flash, so can actually have the flash movie that’s a MP3 player, and also has textual information or pictures to go with the music.

REECE: “What do you do to handle that as a developer?”, I’m thinking here. You don’t provide the different audio and video service for each of the players, you will select one or the other?

JOHN: In the past I’ve published in both QuickTime and Windows Media, and I’ve had versions available in different bandwidths

More recently, I’m tending to begin to approach of using flash video. Because the codec that is actually used in flash video, their compression technologies are getting very good, and very high quality for very low bandwidths. Again, this issue with support or cross platforms support that you are going to find Flash on pretty much 80% of computer that are out there and its quite easy to install. Fallback after that is to have Windows Media and QuickTime which means both MAC and Windows users can view it.

John built his first website in 1995, With a reputation for being The Internet Guru, he has become the Internet go-to guy for his clients and friends by helping them make sense of the online world, solving their problems and making Internet easy. - John's Website

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