View Full Version : how big is a HD file?

2010-06-08, 10:36 PM
i am looking at the iPhone 4
it has a 720p 30fps video camera
with 16gb flash memory (assuming it had no apps and whatnot)

how much time would you be able to actually record video for?
i know SD is approx 2gb for 10 minutes and below is the "tech spec" from apples page

Video formats supported: H.264 video up to 720p, 30 frames per second, Main Profile level 3.1 with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; MPEG-4 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Simple Profile with AAC-LC audio up to 160 Kbps per channel, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; Motion JPEG (M-JPEG) up to 35 Mbps, 1280 by 720 pixels, 30 frames per second, audio in ulaw, PCM stereo audio in .avi file format


2010-06-09, 10:33 AM
Those specs tell us what it supports, but you need to find out what bitrate the iPhone 4 records at. Then we can determine the file size of a recording.

2010-06-09, 08:55 PM

2010-06-11, 01:27 AM
I translated this info from some dutch site, hope it helps.

With the 5 megapixel camera on the back you can film in HD quality because the iPhone 4 can produce images of 720p. The video may contain up to 30 frames per second.

2010-06-11, 07:22 AM
as a comparative guesstimation:
the flip video recorder with 8GB can record 1280x720 HD for 120mins.

..but the non replaceable battery will probably determine the true recording time possible for the iphone - rather than the total storage capacity.

2010-06-11, 11:23 AM
Wolf is probably ultimately correct that you will be limited due to battery life, however, due to the fact that it is a compressed 720p using H.264, the size of the file could vary greatly (depending on the amount of overall compression). I would have to assume that since there is no expandable memory that they are going to use the maximum amount of compression possible to increase the amount of recording time (by keeping the file size as small as possible), which as stated above will only be limited by battery life.

2010-06-11, 11:49 AM
yeah keep in mind this ain't true HD we're talkin about...like uni said, it depends on the level of compression its using, and what type...

that said, the specs you listed are about the same as my droid [records vid in .3gp format using h.263 compression]...just recorded 1 min of vid set to "high quality" and the file size was about 22.5MB...so an hour of footage would run approx 1.3GB [came stock with a 16GB card]

picture quality is still far inferior to even a consumer-grade HD camcorder...good enough for youtube, but don't think i'd wanna use it for DVD- or higher-quality projects tho

2010-06-23, 08:59 AM
thanks guys