[FFmpeg-user] How to get good x264 compression?

texastwister scott_purcell at dell.com
Wed May 9 20:05:37 CEST 2012


Several years ago, I started editing HD video from the Flip video camera down
to a lower (but still HD) resolution to save space.  This invocation worked
well and gave good conversion results -- no significant degradation of
quality:

    ffmpeg -threads 2 -i "$ORIG" -s hd480 -vcodec libx264 -acodec copy
"$NEW"

When I try that with my current version of ffmpeg (FFmpeg version
0.6.4-4:0.6.4-0ubuntu0.11.04.1, Copyright (c) 2000-2010 the Libav developers
built on Jan  4 2012 16:13:16 with gcc 4.5.2), I get:

    [libx264 @ 0x1213e20]broken ffmpeg default settings detected
    [libx264 @ 0x1213e20]use an encoding preset (vpre)

I've tried using presets:

   ffmpeg -i HBC_Baptisms_Spring2012_10_ClosingComments.MP4 -s hd480 -vcodec
libx264 -vpre   normal -acodec copy  -threads 0 -y
HBC_Baptisms_Spring2012_10_ClosingComments.hd480.MP4


   ffmpeg -i HBC_Baptisms_Spring2012_10_ClosingComments.MP4 -an -s hd480
-vcodec libx264 -vpre    slow_firstpass -pass 1 -threads 0 -f mp4 -y
/dev/null  && ffmpeg -i HBC_Baptisms_Spring2012_10_ClosingComments.MP4 -s
hd480 -vcodec libx264 -vpre slow -acodec copy -pass 2 -threads 0 -y
HBC_Baptisms_Spring2012_10_ClosingComments.hd480.MP4

But every thing I've tried has given highly degraded results -- nothing like
the clean results I used to get. 

What am I missing?

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