skottish
30th October 2008, 18:30
I always have a very recent FFmpeg (built today for instance) and am using
x264 r999 (patiently... waiting... and waiting). I started to experiment
with the x264 presets that are shipped with FFmpeg. My question is about
quality and input.
I mainly use x264 to encode my own artwork. All of the frames are GIMP
produced PNG files, so they're 24 bit images (no alpha). If I use the
normal, hq, or max presets nothing seems to change. 4077 frames using this
command line from Robert Swain's guide:
ffmpeg -i infile -vcodec libx264 -vpre hq -b 1M -bt 1M -threads 0 outfile.mp4
produces three files that are 48.8 MB in size with no discernible
difference in quality. Using the same three presets against a test movie
produces a huge difference both in quality and the amount of processing
power it takes to play back with Mplayer. Is this the expected behavior
when encoding from individual frames?
By the way, the same video using the gneneric line:
-coder 1 -flags +loop -cmp +chroma -partitions \
+parti4x4+partp8x8+partb8x8 -me_method hex -subq 6 -me_range 16 -g 250 \
-keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -b_strategy 1 -threads 0
at 2500 kbps produces an ~130 MB file with far lesser quality. Massive
improvement indeed!
As always, thanks to everyone working on x264 and FFmpeg. These are both
supreme pieces of software.
x264 r999 (patiently... waiting... and waiting). I started to experiment
with the x264 presets that are shipped with FFmpeg. My question is about
quality and input.
I mainly use x264 to encode my own artwork. All of the frames are GIMP
produced PNG files, so they're 24 bit images (no alpha). If I use the
normal, hq, or max presets nothing seems to change. 4077 frames using this
command line from Robert Swain's guide:
ffmpeg -i infile -vcodec libx264 -vpre hq -b 1M -bt 1M -threads 0 outfile.mp4
produces three files that are 48.8 MB in size with no discernible
difference in quality. Using the same three presets against a test movie
produces a huge difference both in quality and the amount of processing
power it takes to play back with Mplayer. Is this the expected behavior
when encoding from individual frames?
By the way, the same video using the gneneric line:
-coder 1 -flags +loop -cmp +chroma -partitions \
+parti4x4+partp8x8+partb8x8 -me_method hex -subq 6 -me_range 16 -g 250 \
-keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -b_strategy 1 -threads 0
at 2500 kbps produces an ~130 MB file with far lesser quality. Massive
improvement indeed!
As always, thanks to everyone working on x264 and FFmpeg. These are both
supreme pieces of software.