Effective Living > Technology > Apple | Video
Summary. The Apple iPhone 4 offers high definition video recording at 1280 x 720 pixels of resolution.
Highest Quality Video. A 1280 x 720 resolution video of 9 minutes in length will be about 700MB in it’s native file size when stored in the phone or transferred to a computer. When played directly on a computer, this video looks great. Were this video to be burned to a DVD, it would still look quite good.
Recording Tips. For best video quality, there should be an abundance of diffused light during recording and limited background noise. The video camera and subject should be moving as little as necessary. The touch screen can help with focus and light metering on the subject.
YouTube Upload From iPhone. When uploading to YouTube directly from the iPhone, the HD quality will be lost. This is because a reduced quality video is produced before uploading to save on Internet network bandwidth usage. The 700MB video mentioned above will be reduced to about 37MB, and the loss of about 660MB (about 95% of your original image information) is obviously noticeable. The reduction in file size is achieved by reducing the video size from 1280 x 720 to 480 x 270. In addition to the reduced number of pixels, video compression (like image compression) is used. Normally when reducing a photo or video, you can choose to reduce the dimensions but retain the image quality for a smaller picture that is very crisp and clear. Unfortunately, the video compression used in the upload process with YouTube is not very good. So, the resulting video image is small and fuzzy.
YouTube Upload from Computer. For better quality video, it’s recommended that you transfer the video from your iPhone to your computer and then upload it to YouTube using the video uploader application on your computer or directly from your YouTube account page. This will result in the following compressed videos being available for viewing on YouTube: 1280 pixels wide by 720 pixels high (130MB file), 853 x 480 (81MB file), 640 x 360 (54MB file), and 427 x 240 (28MB file). Regardless of what video you choose to view, the quality is obviously not as good as the original 700MB file since much of the video information has been removed to save file size and bandwidth. However, the HD setting on YouTube should offer the best quality.
Understanding Video Compression. There are two ways to reduce the file size of a photo or video. One method is to retain the clarity and sharpness, but simply reduce the dimensions. The other way to reduce photo or video file size is to reduce the clarity. When saving JPG images, it’s common to see a slider control that allows you to determine the clarity of the resulting image. The same is true for video, unless it is an automated system (as with YouTube uploads).
YouTube Video Quality Comparison. Using the two video samples below, it’s possible to compare by playing them both at the same time (use pause and then play to synchronize).
YouTube Video Sample – 480 x 270. Below is a high definition video sample that was uploaded from the iPhone 4 to YouTube. Notice that the original HD dimensions are reduced during the upload process.
YouTube Video Sample – 1280 x 720 HD. Below is a video sample recorded on the iPhone 4 that was uploaded to YouTube as a 700MB file with full 1280 x 720 HD video. YouTube converted it to be the same dimensions, but a file size of 130MB making it reduced quality from the original.
YouTube iPhone 3GS Video Sample – 640 x 480. Below is a 6 minute video sample that was recorded on the Apple iPhone 3GS. The video was transferred to the computer and then uploaded to YouTube. The original size was 640 x 480 and 160MB. The compressed size retained the dimensions of 640 x 480 (480p), but lost about 75% of the video information and resulted in a file size of 39.7 MB. Surprisingly the quality is still okay.
Video Samples. Below are six samples of the same video that was recorded and edited on the iPhone 4. The first three have been transferred to a computer from the iPhone 4, and then uploaded to YouTube. The next three were uploaded directly from the iPhone 4. They were created using iMovie on the iPhone 4 and exported/saved to three different sizes into the iPhone 4 camera roll. Be sure to select the maximum playback quality for the most accurate comparison.
Below is a video test produced by Gregory Johnson as follows: video recorded on the iPhone 4, edited in iMovie on the iPhone 4, exported from iMovie to the camera roll in 1280x720p format with a resulting file size of 327MB. Then, copied over to the computer and uploaded to YouTube.
Below is a video test produced by Gregory Johnson as follows: video recorded on the iPhone 4, edited in iMovie on the iPhone 4, exported from iMovie to the camera roll in 960x540p format with a resulting file size of 164MB. Then, copied over to the computer and uploaded to YouTube.
Below is a video test produced by Gregory Johnson as follows: video recorded on the iPhone 4, edited in iMovie on the iPhone 4, exported from iMovie to the camera roll in 640x360p format with a resulting file size of 110MB. Then, copied over to the computer and uploaded to YouTube.
Below is a video test produced by Gregory Johnson using the iPhone 4 to directly upload to YouTube a video of 1280x720p that is 327MB.
Below is a video test produced by Gregory Johnson using the iPhone 4 and uploading from the phone to YouTube in 960x540p format.
This is a test by Gregory Johnson uploading a 640x360p video from the iPhone 4 directly to YouTube.