libx264 vs libopenh264 Dataset¶

Compare the libx264 and the libopenh264 encoders.

Download¶

mendevi download x264_vs_openh264.db.xz.torrent

x264_vs_openh264.json.xz (18 Mo).
x264_vs_openh264.db.xz.torrent (6.8 Go).

Plots¶

Distortion as a function of bitrate¶

mendevi plot '<x264_vs_openh264.db>' -x rate -y psnr -y vmaf -wx category -c '(encoder, profile)' -m effort

Consumption as a function of bitrate¶

mendevi plot '<x264_vs_openh264.db>' -x rate -y energy -wx category -wy profile -c encoder -m effort -f "category in {'4K-TV', 'Gaming'}"

Compression efficiency for PSNR=35dB¶

mendevi plot '<x264_vs_openh264.db>' -x rate -y energy -c '(encoder, profile)' -m category -f '34.5<psnr<35.5'

Consumption as a function of bitrate for a psnr of 35dB

Compression efficiency for rate=2Mb/s¶

mendevi plot '<x264_vs_openh264.db>' -x rate -y energy -c '(encoder, profile)' -m category -f '1.8e6<rate<2.2e6'

Consumption as a function of bitrate for a bitrate of 2Mb/s

Compression efficiency for fixed energy¶

mendevi plot '<x264_vs_openh264.db>' -x rate -y psnr -wx 'round(energy/nbr_frames, 1)' -c encoder -m '(profile, effort)' -f "0.29<energy/nbr_frames<0.31 or 2.45<energy/nbr_frames<2.55"

Consumption as a function of bitrate for a fixed energy

Conclusion¶

The main consumption factor is the resolution, not the encoder.
At equal resolution and quality, libopenh264 consumes less energy than libx264.
libx264 has a large variance in energy consumption depending on the preset and the video content. It is therefore much less predictable than libopenh264.

Ressources¶

this paper (Performance comparison among popular implementations of H.264 encoders) compare the distortion of that codecs.

Reproduce¶

for video in ctc/*.mkv; do
    mendevi prepare $video -p sd
    mendevi prepare $video -p fhd
done
mendevi encode reference* -e fast -e medium -e slow -m cbr -m vbr -c libx264 -c libopenh264
mendevi probe sample_* --psnr --ssim --vif --vmaf