[FFmpeg-user] Compressibility Check

Brendan Brewster brendan.brewster at gmail.com
Tue Mar 27 18:04:44 CEST 2012

On Mon, Mar 26, 2012 at 11:53 PM, dE . <de.techno at gmail.com> wrote:

> On 03/27/12 04:52, Brendan Brewster wrote:
>> Hi,
>> I am trying to implement a compressibility check via ffmpeg to determine
>> an
>> appropriate resolution for the full encode.
> Can you please be more clear about what you're trying to do? What do you
> mean by 'compressibility'. Changing resolution is just one of changing
> compression level.

The idea is to take some percentage of the input, say 5%, at various points
throughout and encode this with the default (input) resolution and bitrate.
I have a specific file size to meet, such as DVD5, and therefore know the
bitrate cap in order to fit my output onto the destination media (given a
certain audio bitrate). I can then determine the number of bits per pixel
for the default encode and prepare ratios with regard to lesser resolutions
with the enforced bitrate. We choose a lower resolution if the ratio is
poor. This is what I mean by a compressibility check. Similar functionality
was implemented by the legacy Gordian Knot as well as within Tuxrip.

I would just like to speed up my analysis by avoiding the majority of the
seek time incurred especially in passes that pinpoint points later in the
input video stream. I was really hoping that there might be a way to
achieve the same end via one pass.


More information about the ffmpeg-user mailing list