Multimedia Electronic Mail - Status of Development

Dejan Domjanović

Department of Planing & Research,
Croatian Academic and Research Network
J. Marohnića bb, 10000 Zagreb, Croatia
Phone: +385 1 6129999/584

(CARNet na MIPRO '98)

Abstract - Electronic mail, as very popular electronic medium, is the most common way of communication. Multimedia gives us possibility to extend the way of expressing our thoughts. But there are several problems and disadvantages of multimedia electronic messages. This papers will try to examine do we really need multimedia mail and does it offer as much as it requires.

I. INTRODUCTION

Electronic messages that people may exchange via computers are of various types. They can be composed of text only (plain or rich), voice only, voice and video only, or be any combination of these media types. The term multimedia electronic message is usually reserved to describe a message that contains either a voice or a moving picture combined with text, graphics, or an image.

In this papers electronic multimedia mail is divided into four basic types, according to [1]: electronic audio-mail, electronic video-mail, electronic compound-mail and multimedia mail.

The purpose of this paper is to describe different types of multimedia electronic mail, their advantages and disadvantages, requirements, current status of development and their prospects.

II. ELECTRONIC AUDIO-MAIL

In electronic audio-mail exchanged message is consisted of digitized speech. Message can be entered to the system by telephone or by desktop computer. Workstation used for sending and receiving audio mail must be equipped with microphone, speakers or headphones, and with appropriate sound card (A/D and D/A converter).

Major disadvantage of electronic voice-mail comparing with ordinary text mail is large consumption of memory space. Voice message can consume up to 500 times more memory than equivalent text message (even when compressed). Electronic mail, as very popular electronic medium, is the most common way of communication. Since an ordinary user daily receives and sends relatively large amount of messages, and has a need for archiving them, above mentioned memory consuming becomes real problem, as for the users desktop computer, as for the network.

Fig. 1 Comparison of storage requirements of voice (uncompressed) and text messages

Today almost every e-mail client is capable of sending audio-mail, and some of them offer possibility of creating of voice message inside of them. It is very easy thanks to MIME protocol. Despite the fact that every ordinary e-mail client can easily handle voice messages, electronic audio-mail is not widely used. Most of the workstations used today are not equipped with at least one part of requirement. But major reason for low usage of electronic audio-mail is not the lack of equipment, but the fact that the process of generating the voice-mail is time consuming and usually explicitly user-unfriendly.

III. ELECTRONIC VIDEO-MAIL

Electronic video-mail is analogous to voice-mail, except that the messages include video sequences. There are two basic modes for using video-mail. First mode is video message composed spontaneously by the sender, where the user, instead of composing a text-mail, generates a short audio-visual message. The major objective is to add new dimension to the message. Second mode is video message generated after unsuccessful videophone call. The difference with first mode is that the user had no initial intention of sending a video message.

Fig. 2 Comparison of storage requirements of voice and video

Workstation for sending and receiving video-mail must be equipped with microphone, speakers or headphones, TV camera, a video capture device or board and multimedia-user agent software.

As with the audio-mail, the major problem is large consumption of memory space. Memory consumption differs according to quality of video sequence, and can be few times larger than the adequate audio message.

Sending and receiving of video messages is, like for audio messages, supported by Internet MIME protocol, where the earlier prepared video sequence is added as attachment to standard e-mail message. There are few products developed especially for composing video-mail messages but none of them succeeded as widely used commercial product. Most of it never left the laboratories where it was developed. Next problem is, again, user-unfriendly interface, non-intuitive and low quality of video (considering reasonable memory consumption). Inadequately equipped workstations are even bigger problem than for audio-mail, because the workstation dedicated for handling electronic video-mail requires everything needed for electronic audio-mail plus TV-camera and video-capture device.

IV. ELECTRONIC COMPOUND MAIL

An electronic compound message mixes text with graphics and images. In other words, a compound message is a mixture of any types except audio and video. Such message does not require special devices for its presentation to receiver and remains printable.

According to [1] electronic compound mail cannot be considered as multimedia-mail because it does not include voice and video, but it is necessary to mention it with other types of multimedia mail because it extends simple text-message with additional information necessary for understanding the it. Attachments included in compound-mail can be made during the process of composing the message (hand-written text, sketches or drawings) or prepared before the process of actual composing the message (images and graphics).

V. MULTIMEDIA MAIL

We use the term multimedia-mail for the exchange of messages composed of text (plain or rich), pictures or graphics, supplemented with motion video, audio or computer animation. Multimedia-mail message cannot be printed without losing the part of its information.

Workstation used for generating the multimedia message must be equipped with audio or video A/D device and software or hardware module for compression, at least for video, but is also recommended for audio signal.

As before mentioned types of multimedia electronic mail, multimedia mail also has large memory requirements. Like mentioned before, storage of one minute of digitized speech (uncompressed) require near 500 Kbytes of memory space, while one minute video sequence in near VCR quality, even when the compression techniques are used, occupies around 10 MB of memory. If we have that on mind, video and audio sequences, as the part of multimedia message, must be extremely short. Possibility of storage of such messages is inadequately low, and far from ordinary user requirements. After the message is replayed it must be erased, and since there is no way of printing it, multimedia message is not applicable for the user. The only serviceable usage of multimedia mail is as the additional service for videophony, when we cannot reach the other party, and we want to leave the short message to recipient about our unsuccessful call, like we do on the phone answering machine.

Almost every mail user agent used today is capable of sending and receiving multimedia mail, thanks to widely used Internet MIME standard. Multimedia Internet Mail Extensions (MIME) redefines the format of messages to allow for extensible set of different formats for non-textual message bodies and multi-part message bodies as described in [2] and [3].

VI. CONCLUSION

Usage of multimedia electronic mail today, unfortunately, is not much different than it was two years ago, when after big explosion everything has suddenly stopped. The truth is that users have no much use of all aspects of multimedia electronic mail, so interest in development of multimedia mail applications is low. Another big disturbance is caused by the fact that most of desktop devices in use today are missing at least one component required for composing and presenting multimedia electronic message. Memory requirements and user unfriendliness are much greater than advantages of such messages. Today, when all conditions for development of multimedia services are fulfilled (fast computers, large amounts of memory, bigger network capacity), all efforts are aimed to development of direct communication over network (video-conferencing, Internet telephony) and streaming applications, where the multimedia electronic multimedia mail can represent just additional service if direct communication fails. Only the electronic compound-mail has the bright future as the stand-alone form of electronic mail, and it is already widely used.

REFERENCES

1. F. Fluckiger, Understanding Networked Multimedia, Applications and Technology, Prentice Hall, 1995.
2. N. Freed, N. Borenstein, Multipurpose Internet Mail Extensions (MIME), Part One: Format of Internet Message Bodies, 1996, RFC 2045
3. N. Freed, N. Borenstein, Multipurpose Internet Mail Extensions (MIME), Part Two: Media Types, 1996, RFC 2046