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

[Ronald S. Bultje]

Hi,

On Thu, Jan 10, 2019 at 2:41 PM Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:

> 2019-01-07 18:37 GMT+01:00, Ronald S. Bultje <rsbultje at gmail.com>:
> > Hi,
> >
> > On Mon, Jan 7, 2019 at 12:22 PM Lauri Kasanen <cand at gmx.com> wrote:
> >
> >> On Mon, 7 Jan 2019 12:02:58 -0500
> >> "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:
> >
> > https://blogs.gnome.org/rbultje/files/2014/02/sintel_decspeed.png
>
> Are the relations identical without asm optimizations?
>

I believe so, yes. The theory behind it would be that lack of per-symbol
probability adaptations in CABAC and bidirectional prediction were missing
in VP8, both of which incur a significant runtime overhead. Then, if you
start disabling tools (e.g. CABAC -> CAVLC) this difference would probably
diminish quite quickly.

Ronald