i***1
发帖数: 2534 | 1 http://gizmodo.com/5850493/watch-the-iphone-4s-shoot-video-pret
http://vimeo.com/30606785
http://vimeo.com/30578363
We know the iPhone 4S is a killer still camera—perhaps its greatest selling
point—but how about video? Do the new guts and 1080p bump make a big
difference? Yes. A giant yes. See just how amazing for yourself.
This perfectly-synced test, which used a special bit of rigging to align
both the 4S and a Canon EOS 5D Mark II to capture the exact same scene, says
way more than any Apple marketing verbiage can. With the 5D's settings
matched as closely as possible to the 4S, the two—at least on Vimeo—look
nearly indistinguishable. Yes, if you look closely, the 5D wins. It's got
greater detail, depth of field, doesn't suffer from the iPhone's jarring
rolling shutter problems, and of course has a giant panoply of manual
settings any phone lacks. But the point remains: Apple's created a handset
camera that can shoot pro-grade (albeit limited) video. And for a small,
small fraction of the price. | S*A
发帖数: 7142 | 2 5D2 那个明显胜出啊。iphone 4s 的 tone 差一截啊。
当然 iphone 的做成这样也非常不容易了。我很满意。
但是拿 5d2 来比就过了。 | f*******a
发帖数: 612 | 3 俺回的另外一个帖子转过来算了
拿4s来录1080p的video并不是一个好的选择。
4S的1080p30 video问题不少，采用h.264的格式bit rate
竟然也到了25Mbps，相当于同等质量mpeg2的1080p30的码率，
看来apple没法做到低bit rate，只能牺牲压缩率换取高质量的画面，
反正用户也一般不关心文件大小，不过这样一来基本没有利用上h.264的好处。
另外没有B picture，rolling shutter现象明显，shaky现象明显，等等。
HD video的录制和压缩本身就是一个大计算量的过程，在手机
上所有功能里面可以说是计算量最大的一个任务，又要考虑低功耗，
做好不容易。4s里耗电量大完全正常。apple的芯片开发组里面
的video group看来不太给力，但为了在4s上提供1080p30的spec，
搞成这个样子也就推出了。 |
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