dav1d accelerated AV1 decoder

[lvqcl]

8-bit video: SSE4.1 vs AVX2 vs AVX-512 (on 8C/16T Rocket Lake) - https://code.videolan.org/videolan/d..._requests/1301

[Beelzebubu]

Originally Posted by benwaggoner

Do we know how much speedup AVX512 provided? We've not seen it to be particularly useful in encoder performance, so it'd be interesting if it helps more on the decode side.

dav1d uses the icelake subset (AWS: m6i/c6i, or: F, CD, VL, DQ, BW, IFMA, VBMI, VBMI2, VPOPCNTDQ, BITALG, VNNI, VPCLMULQDQ, GFNI, VAES), not skylake subset (AWS: m5*/c5*, or: F, CD, VL, DQ, BW). Icelake's performance of AVX512 instructions is in general much better than Skylake's, but the wider instruction subset also allows for certain additional code optimizations.

Extreme example of the latter: 8-bit film grain is more than 3x as fast with AVX512 compared to AVX2.

[benwaggoner]

Wow, those are some very impressive speedups with AVX512! The new instructions are making at least as much of a difference than the "AVX2, but 2x wider" instructions.

Of course, Icelake CPUs don't have that much market share yet, but these kinds of speedups are quite promising in the long term for software decoding.

[Beelzebubu]

Originally Posted by benwaggoner

Of course, Icelake CPUs don't have that much market share yet, but these kinds of speedups are quite promising in the long term for software decoding.

... and software encoding!

[Spyros]

dav1d 1.1.0 was released yesterday. (Tag)

Changes for 1.1.0 'Arctic Peregrine Falcon':
-------------------------------------------

1.1.0 is an important release of dav1d, fixing numerous bugs, and adding SIMD

• New function dav1d_get_frame_delay to query the decoder frame delay
• Numerous fixes for strict conformity to the specs and samples
• NEON and AVX-512 misc fixes and improvements
• Partial AVX2 12bpc transform implementations
• AVX-512 high bit-depth cdef_filter, loopfilter, itx
• NEON z1/z3 optimization for 8bpc
• SSSE3 z1 optimization for 8bpc

"From VideoLAN with love"

[hajj_3]

Changes for 1.2.0 'Arctic Peregrine Falcon':
-------------------------------------------

- Improvements on attachments of props and T.35 entries on output pictures
- NEON z1/z3 high bit-depth optimizations and improvements for 8bpc
- SSSE3 z2/z3 8bpc and SSSE3 z1/z3 high bit-depth optimziations
- refmvs.save_tmvs optimizations in SSSE3/AVX2/AVX-512
- AVX-512 optimizations for high bit-depth itx (16x64, 32x64, 64x16, 64x32, 64x64)
- AVX2 optimizations for 12bpc for 16x32, 32x16, 32x32 itx

[hajj_3]

Changes for 1.2.1 'Arctic Peregrine Falcon':
-------------------------------------------

- Fix a threading race on task_thread.init_done
- NEON z2 8bpc and high bit-depth optimizations
- SSSE3 z2 high bit-depth optimziations
- Fix a desynced luma/chroma planes issue with Film Grain
- Reduce memory consumption
- Improve dav1d_parse_sequence_header() speed
- OBU: Improve header parsing and fix potential overflows
- OBU: Improve ITU-T T.35 parsing speed
- Misc buildsystems, CI and headers fixes