[FFmpeg-user] ffmpeg makes some sources darker

[Jim Worrall]

> On 2016 Jan 5, at 4:28 PM, Andy Furniss <adf.lists at gmail.com> wrote:
> 
> Jim Worrall wrote:
>> 
>>> On 2016 Jan 5, at 3:13 PM, Jim Worrall <coniophora at gmail.com>
>>> wrote:
>>> 
>>>> Currently I just get an empty ffmpeg2pass-0.log and pass 1 is as
>>>> slow as pass 2. As expected he result is worse as well.
>>>> 
>>> Uh-oh, I thought that’s what was supposed to happen (except for the
>>> worse result part).  I thought libx264 worked that way.  I better
>>> try it the other way!
>> 
>> I just tested doing pass both ways.  It is true that ffmpeg’s log
>> appears to remain empty, while x265’s does not.  But the output is
>> identical as near as I can tell, and putting pass as an ffmpeg option
>> was actually slightly faster (both passes about the same speed as
>> opposed to pass 1 being a bit slower via x265-params.
> 
> Hmm I just tried release x265 and with ffmpeg both my passes were the
> same time, with x265-parans pass 1 was twice as fast. Quality was a bit
> better min psnr wise with x265. Visually I could only really tell on the
> first 10 frames - it seemed much the same after that. stats below show
> that more was spent on I frames with x265-params.

OK, I bow to your greater knowledge and experience, and will start
using ‘pass’ in x265-params.  Thank you!