Duration Dataset

Allows you to see the impact of video length on compression and energy consumption.

The parameters of this database

Name	Value	Description (link)	Total
video	\(100\) slices	Big Buck Bunny	\(100\)
profile	sd, fhd	video resolution and more	\(2\)
encoder	libsvtav1, libx264	enc_encoder	\(2\)
quality	\(\left\{\frac{k}{3} \mid k \in [1,2] \right\}\)	enc_quality	\(2\)
effort	fast, medium	enc_effort	\(2\)
mode	cbr, vbr	enc_mode	\(2\)
thread	\(\left\{ 8 \right\}\)	enc_threads	\(1\)
repeat	\(10\) times	total repetitions	\(10\)
ramdisk	no	shm in enc_cmd	\(1\)
host	paradoxe-32, yeti-2	env_hostname	\(2\)
metrics	psnr, ssim	Table t_met_metric
total	\(\prod\)	total number of points	\(27054\)

Download

mendevi download duration.db.xz.torrent

• duration.json.xz (24.3 Mo).

• duration.db.xz.torrent (29.8 Go).

Plots

Encoding energy per frame as a function of the number of frames

mendevi plot duration.db -x nbr_frames -y energy_per_frame -e ref_stem -c '(encoder, effort)' -wy profile -wx hostname -t t_enc_encode

Decoding energy per frame as a function of the number of frames

mendevi plot duration.db -x nbr_frames -y energy_per_frame -e ref_stem -c '(codec, effort)' -wy profile -wx hostname -t t_dec_decode

Bitrate as a function of the number of frame at constant quality

mendevi plot duration.db -x nbr_frames -y rate -c encoder -m effort -wx quality -wy profile -f "mode == 'vbr'"

Conclusion

When the video contains enough images, the average energy per frame no longer depends on the duration of the video. Thus, for videos with more than 300 images, ie more than 10 seconds, this effect becomes negligible.

These results are consistent with the UIT-R BT.500-15 (05/2023) which recommends 10-second sequences.

Reproduce

First, generate the video segments

The first step is to extract random length segments from a video.

The video used is bbb.mp4, the length of the segments follows a base-10 exponential probability distribution.

Next, perform the measurements

mendevi encode -r10 -c libx264 -c libsvtav1 -e fast -e medium -m cbr -m vbr -n2 reference*
mendevi probe --no-vmaf reference* sample*
mendevi decode -r10 sample*