We support a wide range of the most commonly used A/V formats, also know as container formats. Some of these are ASF, AVI, DivX, FLV, MKV, MOV, WMV, MP4, MPEG and XviD. Each of these formats may contain any number of streams, which usually consists of one video stream and one or more audio and subtitle streams. For the purpose of uploading videos here however you should limit the number of streams to two. One for Video and the other for audio. We do not have the facilities available to decode or otherwise display subtitle streams or anything else that is specifically not audio and video. If you want subtitles on your video, you'll need to encode them into the video stream itself. Your soundtrack may be either mono or stereo. Our encoders don't know what to do with soundtracks which have more than 2 channels. The result is often no sound. If you have a soundtrack that has more than 2 channels, it must at least be down-mixed to stereo before you upload your video.
The specifications by which the audio and video streams are compressed (while encoding) and expanded (while playing) are better known as audio and video "codecs". The word "codec" is the short form of "coder-decoder", which is exactly what the codec does. If you think of the container format as a suitcase and the audio/video parts as various articles of clothing for example, the codec is what folds all of the clothes and packs them neatly into the suitcase.
Each of the supported container formats has its own list of supported audio and video codecs. The exact combinations of what codecs may be used with each container format is too long for this FAQ. You usually won't need to worry about such technicalities though as most encoders will not allow you to make bad mistakes, like using the wrong codec in a container. There are however still codecs that produce very good results and those that don't.
For the specific purpose of uploading files here, keep in mind that the end result is going to be re-encoded one more time before it reaches it's final destination, your audience. This final re-encoding of the video is where most of the loss in quality can happen, especially if your uploaded video is of inferior quality. So in the interest of keeping your upload times to a minimum, you'll need to choose a video codec that is very efficient in compression yet yields exceptional quality.
Our tests have proven that this may be achieved by using any video codec which utilizes an MPEG-4 style of encoding. This may be MPEG-4 itself or DivX (or XviD, DivX's half brother). H.264 also works well. Most of the MPEG-4 style codecs will fit well into the MOV or AVI containers, as well as a couple of others mentioned in the first paragraph.
Audio is not as much of a concern because it's the video which has a tendency to eat up as much as 3/4 of the files size. Just as with the video, you also have several choices of audio codecs. However for simplicity we're going to narrow this down to two basic choices. Normal and high quality. If you're producing a video where the audio is not crucial and you're running short on time or bandwidth, most people won't notice if you skimp just a little bit on the audio. On the other hand, if you're a band and you're putting together a music video then the quality of the audio becomes more significant.
For normal quality audio, any MPEG audio codec will do. MP3 is just fine. For high quality you would certainly want to go with a lossless codec such as WAV, AU or AIFF in 16-bit stereo with a sampling rate of at least 44K.
You may need to experiment a bit with your encodings before actually uploading a video. If the video becomes blocky, blotchy or the colors begin to bleed, try applying more bandwidth to the video stream and re-encoding. This bandwidth is known by most encoders as the video bit-rate. The slightest loss of quality in the source video may be amplified up to as much as 4X once our encoder converts your video to its final flash format.
If you want a more simplified explanation, you may wish to try one of our visual tutorials. Those cover Apple iMovie and Windows Movie Maker. The settings which are used in those examples are a good place to start for the novice.
Aside from the usual formats, we also support things such as DV straight from your video camera and some others which may very well remain undocumented. Many of these formats are impractical for the purpose of uploading because they produce inherently large files, unless your video is tiny. At this time, we do not prohibit the usage of these other formats and our tests have proven them to be at least functional but there is no guarantee that they will function properly.
For the moment, we do not support 3GP (cellphone) video. This video will have to be downloaded into your computer and converted to one of the other supported formats for uploading. We hope to support 3GP in the near future!
Finally, if you have a question as to whether or not a video will encode properly, you are welcome to try uploading it.
If you have a question as to whether or not a video in a particular format will encode properly, you can try uploading it. It's unpredictable but in any case will not harm our system. Indications that the format cannot be encoded properly are:
- The video never appeared in your account
- A blank video appeared in your account
- Some abnormality with the video itself such as: one frame, video will not play, video but no audio, or vice versa.
If you are having a problem uploading a common format, please contact us and we will try to address the problem.