[Frameworks] single frames online?

[Alistair Stray]

The only way to guarantee really good results with H264 and rapid changes I
guess is to set the Keyframes to 1 so basically you just get a stream of
I-Frames (as in fully encoded stills). Basically an Intra file, a file with
a GOP of 1 (group-of-pictures). Wherever you host it though is going to
reencode it with a longer GOP, but vimeo will at least allow you to make
the original file downloadable. The file will have to be very large though
compared to a normal H264 encoded file, as you'll need to set a high
bitrate to make sure you're not starving the I-Frames. For example the
AVC-Intra flavour of H264 has a fixed bitrate (CBR) of 100Mbps. When I set
my camera up to shoot in an Intra format I have it running between
120-140Mbps as I don't have the luxury of 2 pass encoding etc.

However a good H264 encoder should cope with what your film contains. The
mainconcept encoder for example (which is very tweakable) would use scene
change detection to automatically start a new GOP where the frame changes
dramatically. What would happen to it on vimeo when it rencodes it to
stream though is out of your control.

Also, you could try giving vimeo a file with a much higher bitrate (say
30-40Mbps or so), it'll encode it down to a lower bitrate but at least it
has a better start point. It may also simply be that the encoder you're
using is doing a poor job of scene detection/rapid change within such a low
bitrate (as the Vimeo recommendations), and when vimeo encodes it the
problem gets compounded, so reencoding with a higher bitrate may solve the
problem.





On Mon, Sep 17, 2012 at 2:08 AM, ev petrol <epetrol2 at yahoo.com> wrote:

> hey folks
> has anyone found a good way to compress a film with a lot of single frames
> for the web?
> had a go here, followed the specific vimeo compression suggestions:
> vimeo.com/moiratierney/are-we-there-yet
> but the result is pretty bad (the single frame stuff comes in at 5:15)
> cheers moira
>
> moiratierney.net
> vimeo.com/moiratierney
>
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