[FFmpeg-user] Specifying lib path when building ffmpeg

[Carl Eugen Hoyos]

2016-11-16 17:18 GMT+01:00 Matteo Naccari <Matteo.Naccari at bbc.co.uk>:
>> (I am assuming here that libturing is both slower and produces worse
>> quality than libx265, if this is not true, the following has of course little
>> relevance.)
>
> According to the reference I've circulated before we achieve a lower
> compression penalty but we are slower than libx265.

Not sure I understand.
(Please correct me if the following is wrong / is not what you are saying:)
You argue that to measure the quality of an encoder, it is not necessary
to decode the output bitstream and compare with the decoded bitstream
of other encoders but that it is sufficient to analyze and compare two
bitstreams - what quantizers are used - and the filesizes (and the time
encoding needed)?

> Like I said this codec is a live project in continuous development.

Which non-obsolete encoder project (including x264) is different?

>> I don't think comparing to a reference implementation makes
>> sense if better implementations exist and are used.
>
> The coding efficiency provided by the HEVC reference implementation
> (i.e. HM) gives you the "theoretical" limit a standard can achieve.

(Still not sure if I understand)
Are you saying here that a relevant comparison between two
implementations of a video standard is to let both encode a source
file at the highest possible quality mode and then look which one
achieved better quality?

I am sorry that my knowledge about comparing video codecs is
so limited: I thought you choose an input sample and an output
filesize for which you assume a "good" encoding is possible but
limitations will be visible (for the educated viewer). You then test
if the implementations are able to reach the given filesize in an
acceptable time (upper limit), then you decode both output files
and compare them: Either (easy and uncertain) using psnr, ssim
or something similar or (much more difficult but more exact)
visually.
That's how it was done over the last decade, no?

[...]

> http://www.bbc.co.uk
> This e-mail (and any attachments) is confidential

Please remove this from your mails!

Carl Eugen