[FFmpeg-devel] Video codec design for very low-end decoder

Lauri Kasanen cand at gmx.com
Sun Jan 13 18:23:57 EET 2019

On Mon, 7 Jan 2019 12:37:01 -0500
"Ronald S. Bultje" <rsbultje at gmail.com> wrote:

> On Mon, Jan 7, 2019 at 12:22 PM Lauri Kasanen <cand at gmx.com> wrote:
> > "Ronald S. Bultje" <rsbultje at gmail.com> wrote:
> >
> > > Have you considered vp8? It may sound weird but this is basically what
> > > vp8 was great at: being really simple to decode.
> >
> > VP8 has a reputation of being slow, so I didn't consider it. Benchmarks
> > show it as decoding slower than h264.
> It is faster than h264 when comparing ffh264 vs. ffvp8

I tried VP8 on the target platform (libvpx 1.7.0). It took 32% longer
to decode the test vid than xvid, and given xvid was already a bit
under realtime, VP8 is out.

Curiously, VP8 also added very objectionable artifacts. Some blocks
*moved* around in frames. That looked very bad, neither xvid nor h264
caused that, they were just blocky or blurry. VP8 also looked worst of
the three, by eye.

x264 "everything disabled AFAICT" actually looks very good for the
bitrate. Too bad I can't use H.264 due to the patent situation, so not
going to spend time benching it either.

Settings used:

vpxenc -p 2 --profile=3 --target-bitrate=250 --best --end-usage=vbr
--codec=vp8 --min-q=0 --max-q=60 --ivf

mencoder -ovc x264 -x264encopts

(tune=fastdecode disables deblocking, the result file confirms all
heavy options are off)

- Lauri

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