Category Archives: General

Taxes and section 174

7 years since my last post (2017!), so many exciting things to talk about: the AV1 video codec was released, we at Two Orioles wrote an AV1 encoder (Eve) and decoder (dav1d). Covid happened. I became a US citizen. Happily … Continue reading

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Writing x86 SIMD using x86inc.asm

In multimedia, we often write vector assembly (SIMD) implementations of computationally expensive functions to make our software faster. At a high level, there are three basic approaches to write assembly optimizations (for any architecture): intrinsics; inline assembly; hand-written assembly. Inline … Continue reading

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Overview of the VP9 video codec

When I first looked into video codecs (back when VP8 was released), I imagined them being these insanely complex beasts that required multiple PhDs to understand. But as I quickly learned, video codecs are quite simple in concept. Now that VP9 is … Continue reading

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Displaying video colors correctly

Uncompressed (e.g. decoded) video frames are almost universally structured in planar YUV arrays containing lines of pixels. These YUV pixels will then be drawn on-screen, e.g. using a GL shader to do the YUV-to-RGB conversion. It sounds so simple, right? All you’d … Continue reading

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The world’s best VP9 encoder: Eve

VP9 is a bit of a paradox: it offers compression well above today’s industry standard for internet video streaming (H.264 – usually created using the opensource encoder x264), and playback is widely supported by today’s generation of mobile devices (Android) … Continue reading

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VP9 Analyzer

Almost a year ago, I decided to quit my job and start my own business. Video coding technology in general, and VP9 specifically, seemed interesting enough that I should be able to build a business on top of it, right? … Continue reading

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VP9 encoding/decoding performance vs. HEVC/H.264

A while ago, I posted about ffvp9, FFmpeg‘s native decoder for the VP9 video codec, which significantly outperforms Google’s decoder (part of libvpx). We also talked about encoding performance (quality, mainly), and showed VP9 significantly outperformed H.264, although it was … Continue reading

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The world’s fastest VP9 decoder: ffvp9

As before, I was very excited when Google released VP9 – for one, because I was one of the people involved in creating it back when I worked for Google (I no longer do). How good is it, and how much … Continue reading

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Brute-force thread-debugging

Thread debugging should be easy; there’s advanced tools like helgrind and chess, so it’s a solved problem, right? Once upon a time, FFmpeg merged the mt-branch, which allowed frame-level multi-threading. While one CPU core decodes frame 1, the next CPU core will decode … Continue reading

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Microsoft Visual Studio support in FFmpeg and Libav

An often-requested feature for FFmpeg is to compile it using Microsoft Visual Studio’s C compiler (MSVC). The default (quite arrogant) answer used to be that this is not possible, because the godly FFmpeg code is too good for MSVC. Usually … Continue reading

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