[x264-devel] Re: Scalability

[Limin Wang]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Hi,

* Christian Bienia <cbienia at CS.Princeton.EDU> [2007-02-28 13:43:10 -0500]:

> Hi,
> 
> > For testing, change the #define X264_THREAD_MAX 16 (in common.h) to some
> > bigger number. Then I'll see about dynamic allocation.
> 
> The performance doesn't improve significantly with more than 16 threads. Here's the results with a sufficiently high X264_THREAD_MAX value:

X264_THREAD_MAX is only one limitation, see below code:
    h->param.i_threads = x264_clip3( h->param.i_threads, 1, X264_THREAD_MAX );
    h->param.i_threads = X264_MIN( h->param.i_threads, 1 + (h->param.i_height
    >> h->param.b_interlaced) / (X264_THREAD_HEIGHT + 16) ); // FIXME exact limit?

So in your case, actual threads will be 
interlaced: 1+(1080 >> 1)/(24+16) = 13
not interlaced: 1+1080/(24+16) = 27

In my opinion, it's better for x264 to return error if input threads exceed
X264_THREAD_MAX instead of clip it directly.


Thanks,
Limin
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.6 (GNU/Linux)

iQEVAwUBReYy+kztbf7dKiuoAQIADQgAgw5J+64/KIi81zfMoCqrIEGP3QT5jIzo
dXGdsT/uZW6EM9cPFlgtLs+QA0cUAGKPcVs/zg8eGMjnIxU47MnBc8oXId6fn7Wo
GMBIFd+Nj9KehlKj8rCqLChqynBkV7fWc3fbwBRIWDDlFjUXXNVBD9YDXGrvVXUe
nVN7kQB06RE05jbGKZguTNS3IYVBNR5BgqbAFW9sMQSrsd7MYbq3XyiJHc0sBQmO
WYztZ1gGgTcnGKoG+ajsoRbYJirWH5/UjCV58ei5zPAtgn74Me8xhhXkVRsTeeqw
ST+wUYQGZy5TEx4bavC8kcq0VsTgQy5p1koq8lNxDYmtc1iZdeVqvw==
=G3Gq
-----END PGP SIGNATURE-----

-- 
This is the x264-devel mailing-list
To unsubscribe, go to: http://developers.videolan.org/lists.html