SWF (acronym of “Shockwave Flash”) actually is a Flash movie, and it can be viewed as a Flash animation format, while the FLV is Flash Video, Flash Video is the name of a file format used to deliver video over the Internet using Adobe Flash Player .
More specifically, SWF is a proprietary file format for multimedia and especially for vector graphics. It can contain animations or applets of varying degrees of interactivity and function in order to be small enough for publication on the Web. Therefore, SWF is currently the dominant format for displaying animated vector graphics on the web which is very popular and be commonly used. What’s more, SWF is sometimes used for creating animated display graphics and menus for DVD movies, and television commercials.
FLV, as a Flash video format, is also very popular on the web. You can always see the videos on the website like YouTube, Google Video, MySpace TV. After you download the video from YouTube, you will find the downloaded video’s file extension is .flv, which means it is the FLV video. It is also in a small size and can be loaded on the web easily. We can take the YouTube video as an example, the video on the website we can consider as a FLV files with a player in it. Once you download it to your local computer, you just download the content, that is the FLV, to your website, but the player is still on the YouTube website. If you want to play the FLV on your website, you need to embed it to a player. While the SWF can be seen as a container and we can embed the FLV files into SWF and play it. So, under some conditions, SWF file can be divided into two parts, the Flash Video (animation content) and the SWF player (Adobe Flash Player is commonly used to play the SWF).
What you should know about Flash and streaming Flash video…
Anyone who’s serious about putting video on the web needs to take a close look at Flash and Flash video (FLV). But for newcomers to internet video, this can be quite confusing. In this article, I’ll tell you everything you need to know (but nothing more) so you can make the right decisions about adding video to your web site…
When it comes to using Flash to deploy web videos, you have three main options, all of which require the use of a Flash SWF file:
- Embedded Video - An embedded video is a single file which contains both the player, and the video file itself (embedded within the SWF). Results in lower quality video that must be downloaded in full before viewing.
- Progressive Download - In this method, the video content (the FLV file) is kept seperate from other Flash content and the the video player itself. Video starts to play quickly. Easy and inexpensive to accomplish with very good results.
- Streaming Video - When you stream video, FLV files are kept seperate from other Flash content. This method is a more complicated and expensive of displaying video, but also enables publishers to control nearly every aspect of the video experience.
Take a closer look at each of the options…
1. Embedded Video (SWF)
Embedded video files (SWF) are usually best for shorter videos. An embedded video is a single file which contains both the player, and the video file itself (embedded within the SWF).
When you publish an SWF Flash movie, the video is fully contained in the SWF file. The only requirements are a normal web server to deliver the video.
Pros and Cons of Using Embedded Video
- Lower video quality - A lower quality codec is used to encode video when it is imported into Flash, resulting in lower quality presentations.
- Large SWF files = long download times - This method dramatically increases the size of your SWF file, resulting in long publishing times and poor viewing experiences for your visitors. This is because the view must wait until the SWF is completely downloaded before playback begins.
- Content not easily changed - Making a change to the video can be tedious because you must reimport the video, make adjustments, and then republish and re-upload the SWF file.
- Audio sync concerns - The frames-per-second (FPS) rate of the video and the Flash movie must match or else the audio and video will be out of sync.
- Lack of support for long video clips - There is a limit to the number of frames that Flash can accept, so you may not be able to import larger videos.
- Frame limit - SWF files have a limit of 16,000 frames. If your video is longer than a few minutes, it will probably exceed this limit - meaning: it won’t play.
- Size concerns - SWF files tend to fail (or play poorly) when the file size exceeds the 5-6MB range.
When to Use Embedded Video
Some people will simply find it easier to create and upload just one SWF file to the web in order to get their video online. The results are not as good, but it is slightly faster.
Because of these limitations, this method is only recommended in cases when you the video is short and small. SWF files tend to be better for movies of computer screenshots with fewer colors and minimal screen activity.
2. Progressive Download (FLV)
In this method (a.k.a. “pseudo-streaming”), the video content (FLV file) is kept seperate from the other Flash content and the the video player (SWF file).
When a web page loads, it automatically downloads the smaller embedded SWF file (player). When a visitor elects to view the video, the FLV video file starts downloading to the user’s computer.
The FLV is served from a normal web server through an HTTP request just like a web page or any other downloadable document (e.g., PDF file, text file, etc.).
Unlike with many other methods of video delivery, however, with progressive downloading, the file starts to play before it has completely finished downloading.
Pros and Cons of Progressive FLV Downloading
By keeping the video separate from the SWF file, there are a number of benefits over the previous embedded video technique, including:
- Easy to update - It’s relatively easy to add or change content independently of the video player itself, without having to to republish the SWF file.
- Small SWF file size - Your SWF file (player) can remain very small for fast page loads, while the video only starts to download once the user has requested it.
- Better performance - Because the FLV and SWF files are separate, the performance and results of your video playback will normally be much be better.
- No frame limit - FLV files do not have the 16,000 frame limit.
- Effective RAM utilization - FLV files are handled by a computer’s RAM differently, and more efficiently than the normal embedded SWF video files.
- No FPS syncing concerns - Sync issues between the fps rate of the video and the fps rate of the SWF file are not a problem with progressive downloading.
- Caching of file - If the use chooses to watch the video again, the file plays back from the local cache without the user having to download it from the web again. Result/Benefit: immediate playback and no additional bandwidth usage.
When to Use Progressive Download
Results vary, from good to excellent, depending upon the software you use for converting your files to FLV. Regardless, FLV files are well-suited to full-color multimedia presentations and videos with much screen activity.
If your videos are more than a minute or so long, and you are concerned about the quality of the presentation, you will want to use the progressive download method where an SWF file requests the FLV video file.
With progressive downloading, the file is downloaded and physically resides on the viewer’s machine. Some users will be able to search their browser caches or temporary Internet files and access the content.
In most cases, this probably won’t be a problem. But if you’re selling your video content, and you’re concerned about restricting the usage and viewing of your video content, the following may be a better option…
3. Streaming Video (FLV)
As is the case with progressive download, with streaming video, FLV files are kept external to the main Flash SWF content. But to do “true” FLV video streaming, you need to have your video hosted and served on a server running special streaming software, Flash Communication Server MX.
Pros and Cons of Streaming FLV Video
In the case of streaming video, each client opens a persistent connection to the streaming video server, which streams the video content to the requesting visitor. The video data is “consumed” by the viewer, and then immediately deleted.
This connection between the server and the viewer, and the server’s ability to precisely control and deliver any portion of stream at will, enables the developers and video producers to take advantage of a number of advanced capabilities.
Unfortunately, along with those additional features come additional costs and complexity.
People who do not want the hassle and expense of buying and maintaining server hardware and Flash Communication Server software can utilize the services of hosting companies who offer this streaming service. Fees are based upon usage and storage space, and typically start in the area of $500 per month, or more.
When to Use Streaming FLV Video
If cost is not an issue, but protecting your video content is - then you should take a closer look at a true streaming solution (e.g., VitalStream).
Otherwise, an affordable and effective alternative can be found right here. You get many of the same benefits of true streaming when you use the WebVideoZone Player on your web pages - including:
- The ability to provide interactivity to your video experiences
- Usage tracking and statistics gathering
- High-speed delivery of large files
- Easily customized/edited web video presentations
- Ability to deliver video to multiple viewers at the same time
Flash Video - Summary
In most cases, you will want to use the progressive/pseudo-streaming for your web video.
All you need to do is convert your video to FLV, upload it to the web, and create your video player. It just couldn’t get any easier to add powerful web video presentations to your web site.