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Bug 725051 - x264enc: allow lossless compression (qp=0)
x264enc: allow lossless compression (qp=0)
Status: RESOLVED FIXED
Product: GStreamer
Classification: Platform
Component: gst-plugins-ugly
git master
Other All
: Normal enhancement
: 1.3.1
Assigned To: GStreamer Maintainers
GStreamer Maintainers
: 725033 (view as bug list)
Depends on:
Blocks:
 
 
Reported: 2014-02-24 10:48 UTC by Dirk Van Haerenborgh
Modified: 2014-02-26 08:18 UTC
See Also:
GNOME target: ---
GNOME version: ---

Attachments
Proposed patch (2.80 KB, patch)
2014-02-24 10:48 UTC, Dirk Van Haerenborgh 		committed Details | Review

Description Dirk Van Haerenborgh 2014-02-24 10:48:38 UTC 
Created attachment 270105 [details] [review]
Proposed patch

As described on the ffmpeg x264 encoding guide [1], lossless compression in h264 is possible by setting qp to zero in constant quantizer mode.

With x264enc, this is not possible since the properties 'quantizer', 'qp-min', 'qp-max', and 'qp-step' cannot be set to zero.

This patch addresses this by changing the minimum value from 1 to 0.

[1]: http://trac.ffmpeg.org/wiki/x264EncodingGuide#LosslessH.264
Comment 1 Sebastian Dröge (slomo) 2014-02-25 20:52:43 UTC 
*** Bug 725033 has been marked as a duplicate of this bug. ***
Comment 2 Nicolas Dufresne (ndufresne) 2014-02-25 21:00:13 UTC 
Looks fine to me, though is that a new feature in recent x264 ?
Comment 3 Sebastian Dröge (slomo) 2014-02-26 08:18:46 UTC 
commit e15eb270f92d68a842fc814084a6d62f7e795eca
Author: Dirk Van Haerenborgh <vhdirk@gmail.com>
Date:   Mon Feb 24 11:42:00 2014 +0100

    x264enc: allow lossless compression (qp=0)
    
    https://bugzilla.gnome.org/show_bug.cgi?id=725051