Before you begin:

MPEG (pronounced EMM-PEG), is an acronym for Moving Picture Experts Group which is the ISO committee that sets standards for the audio and video formats under their purview. Before ISO standards were applied to computer technology, every software and hardware vendor used their own system for creating, playing or displaying multimedia files. Now by adhering to committee standards software developers and hardware manufacturers can create products that will interact without any direct consultation between the companies or designers.

The primary advantage of the MPEG format is that the compression algorithm produces relatively small size and high quality media files. Until recently, creating MPEG movies required special hardware, but of late, with the general use of more powerful computers, software conversion has become a practical reality. This new generation of computers equipped with fast, accurate CD burners and the popularity of DVD players has created a new, do-it-yourself market niche for creating CD audio disks and video CD's that was long ago anticipated by the Moving Picture Expert Group.

The MPEG standard addresses both audio and video which is often confusing. The actual scheme for MPEG file extension convention has been long overlooked and abused. In practice MPEG movies, which consist of an audio and video stream use MPEG, MPE, MPG and DAT interchangeably as file extensions. MPEG audio files contain only one stream and generally are saved with MP2 or MP3 extensions which may or may not accurately reflect the audio layer. Most modern media players are capable of playing the file properly regardless of the format or file extension by reading the file header and counting the streams. Some DVD players however are a bit more finicky requiring specific adherence to MPEG standards as well as size, frame rate and audio sampling. There are several MPEG standards for video CD beginning with CD-i, which was created for a CD Interactive market that never really developed. MPEG-1 VCD, MPEG-2 Super VCD and MPEG-2 DVD each improved the resolution and data transfer rate of the standard media.

Getting Started with Fx MPEG Writer

Picking a source file:

Clicking the Browse button open a window that will permit you to navigate all available drives to find a source file.

Supported types for the full version are MPEG, AVI and Windows Media.

You may select a filter from the dropdown list to show a specific type of file in the browse window or you can select All Files (*.*) to shown files that you know to be supported that have other extensions. For example an MPEG file with the extension DAT or a Windows Media file with an ASF extension will open when selected. Once selected the size of the source file will be displayed instead of the prompt.

Fx MPEG Writer can alter video height and width during conversion to comply with various MPEG VCD and SVCD requirements but it does not alter the audio track and thus cannot convert a movie that has no audio. We do however produce another product called Fx ReSound which can add audio to silent movies or you can download VirtualDub free to accomplish the same task.

Setting a target:

Unlike the browse for source which permits you to find an existing file, browsing for a target may in fact be browsing for a file that does not yet exist. You may of course select an existing file or you may browse to the folder where you want the file saved and type a new file name into the text box.

If you have MPEG Files selected in the Save as type drop down MPEG will automatically be appended to the file name that you typed in. You may change that extension to DAT, VCD or any other extension that might be required by another software package. You can of course also change the name after the save.

Selecting a format:

You may select a supported output format from the drop-down list.

Exactly which format you should choose depends upon the purpose of your output, the requirements of any intermediary or playback software and the power of your computer.
If you have a full version of Fx MPEG Writer and you don't see the MPEG-2 options, you must enable MPEG-2 Encoding first by agreeing to the terms of the patent holders.

For this tutorial we captured the Dolby and THX promo lead-in for a Laser Disk Movie. The clip is short but it has enough audio and video data to provide us with a good test while keeping us out of copyright trouble.

The capture mode and target format are somewhat limited by the net power of your computer system. For example, capturing to DVD quality on the average computer is a waste of time and resources. A typical 1,000 MHz P-IV will drop 15% of the frames. For our example we saved to an AVI file then converted to and MPEG-1 with VCD extensions and to an MPEG-2 with Super VCD extensions. Because our computer lacked the power and resources the MPEG-1 version played back better than the MPEG-2. See the chart at the bottom of this page for details.

There are standard resolutions, frame rates and bit rates for the various disk formatting schemes. You should consider your target audience's equipment when creating media. If for example you want all your friends with computers to be able to view your video, don't create DVD disk. Computers must be equipped with DVD players and software to play back DVD. On the other hand, if you target audience will be watching your video on DVD players and never watching on a computer, DVD is the logical choice. If your target audience is mixed, VCD is probably your best choice although some DVD players don't play VCD.

The chart below lists the various formats and their related specifications.

	VCD	SVCD	CVD	DVD
Resolution NTSC PAL	352x240 352x288	480x480 480x576	352x480 352x576	720x480 720x576
Video Compression	MPEG1	MPEG2	MPEG2	MPEG2
Audio Compression	MPEG1	MPEG1	MPEG1	MPEG1, MPEG2, AC3, DTS, PCM
Size/min	10 MB/min	10 - 20 MB/min	10 - 20 MB/min	30 - 70 MB/min
Min per 74 min CD	74min	35-60 min	35-60 min	15-20 min
Hours/DVDR	-	-	-	2-4hrs
DVD Player Compatible	Yes	Yes	Yes	Yes
CPU Demand	Low	High	High	Very High

The amount of time required to save your file depends upon your computer's resources, the size of the input file, the bitrate, the frame rate and the number of concurrent tasks that your computers CPU is also running. Under any circumstances, saving a big file is going to take a long time so it might be wise to start your conversion to run during a time when you don't need your computer.

Creating a Video CD

A Video-CD contains MPEG-1 video sequences which conform to the "White Book" standard that was created by Philips and JVC in 1993. The first track of a Video CD contains the CD-i play program, the CDI, MPEGAV and VCD directories based on the ISO 9660 file system. The next tracks are in the format CD-ROM/XA-Mode 2/Form 2 Sectors and contain the MPEG encoded audio/video sequences that are listed in MPEGAV.

Video-CDs can be played on CD-i players, some Video-CD players or on a PC based CD-ROM drives with CD-ROM/XA support and MPEG decoder software.

VideoCD supports the following formats:

• 352x288 with 25 frames a second (PAL)
• 352x288 with 29.97 frames a second (NTSC)
• 704x576 as single frame
• 704x480 as single frame
• 352x288 with 29.976 frames a second (Sometimes called "FILM" resolution)

For our tutorial we used Nero Burning but the process is similar with any CD authoring software.

We selected Video-CD from the New Compilation wizard and have checked the option to create a standard compliant CD...

We won't go through the detailed setting for Nero here since you might be using some other burning software. When the wizard closes we see a typical Windows explorer-like view in the right panel and the disk layout in the left. Because we're creating a Video CD Nero creates the folders CDI, EXT, MPEGAV, SEGMENT and VCD by default so all we have to do is drag our movie(s) onto the new disk image.

Nero is smart enough to recognize complaint source files. If we had dragged the wrong format onto the video space it would have displayed an error message.

VideoCD V2.0 (VCD) is a standard used to save audio/video data to a CD to be played back by CDI or DVD players. The audio/video data streams are compressed with MPEG-1, Audio Level 2 and played in real time at 75 blocks per second. Because this format and audio/video data generally tolerate bit errors, the space that is normally needed for error correction can be used for MPEG data instead which increases the amount of user data in a block from 2048 to 2324 bytes per block. This gives the VCD 13% more capacity compared with MPEG file storage on a data CD.

The Super VideoCD (SVCD) format is an extension of the VCD standard in which the MPEG-2 compression standard is used with variable bit rate coding which allows twice the bit rate of the VCD. As a result the SVCD also offers enhanced image quality, however total playing time is reduced when the full bandwidth is actually used. At maximum bit rate, an SVCD only stores around 35 minutes of video as against 70 minutes on a VCD.

The default folders created for Super Video CD are not the same as those we created for our VCD.

An (S)VCD is an XA disk with several Mode-2 tracks. The first track usually contains Form-1 blocks with the normal 2048 bytes per block and stores a CD-ROM (ISO) image so that the CD can be read by a PC. Certain files and directories are required by the standards:

• (S)VCD: Information about the available tracks and how they must be played
• EXT (VCD only): More detailed information about the type of playing; only relevant for CDI players
• CDI (VCD only): This directory contains the Philips CDI application and its utilities. These files are licensed by Philips and taken from the Nero root directory. This application is needed for playing tracks on a CDI player.
• MPEGAV (MPEG-2 for SVCD): The AVSEQxx files contain the MPEG tracks on the Video-CD. The first track only contains references to the data which are stored not in the first track but in the subsequent tracks. This means that although these files have a long nominal length they do not require much space in the ISO track.
• SEGMENT: The ITEMxxxx files represent the encoded single pictures. They are stored in the first track as Form-2 blocks and have a fixed length of 150 blocks.

The encoded files can be played on a PC provided a suitable package such as Windows Media Player is installed. DVD player software is required for MPEG-2.

Other files and directories can be added to the CD-ROM. These are ignored by a player. (S)VCD also supports other special functions such as karaoke and hierarchical menus with pictures, but these are not used by Nero at the present time. Nero simply takes a list of MPEG or picture files and writes them to a CD in such a way that playing starts immediately with the first file, and the player's forward and reverse keys can be used to skip from file to file.

You can set a pause that stops play at the end of every file. The pause is only a value in the description of the file so there is no need to create empty blocks; the pause can be very long or can even be set to infinite, in which case the player is stopped and waits for an input from the user.

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