Good Quality DOSBox Video Capture (2020) | Hacker News Reader

Good Quality DOSBox Video Capture (2020)

susam.net

40 pointsingve23 comments

I’ve been impressed by DOSBox-X lately, which works slightly better if you find yourself wanting a more faithful DOS and Windows environment. It’s also got more menus for common tasks than raw DOSBox.

https://dosbox-x.com/wiki/DOSBox%E2%80%90X’s-Feature-Highlig...

DOSBox Pure is also really good, it’s a fork made for RetroArch/libretro and works really well with some special features added https://github.com/schellingb/dosbox-pure

But there are a lot of forks to choose from https://github.com/dosbox-staging/dosbox-staging/wiki/DOSBox...

+1 to DOSBox-x, it's great - e.g. better choices for MIDI, and supposedly also support for Windows 98, although I didn't manage to make that work yet.

Yeah, I've got a pretty full environment with Office, old versions of Visual C++ and Visual Basic, even Encarta 95, and of course Castle of the Winds. No real justification for all this, obviously, beyond occasionally remembering software used to be snappy.

"DOSBox Staging" added in some killer features (chorus and reverb for Adlib) that DOSBox-X currently lacks.

It might not sound like much, but the Sound Blaster AWE64 had that feature, and it really makes Adlib music come alive.

IMHO the best way to capture video from any operating system is to simply output the HDMI to a HDMI USB capture device [1] plugged into another computer running OBS Studio or similar software.

[1]: https://www.walmart.com/ip/HOTBEST-HD-HDMI-Capture-Card-for-...

Pretty much overkill when doing DOS emulation, cost-wise and usability-wise. Either you use dosbox' built-in capturing facility or you just screen capture using OBS on the same machine.

That's probably the easiest, when combined with a HDCP stripper if necessary.

It's unlikely to be high video quality though, as all of the similar HDMI capture devices that I have (~7, known as the "Can'tLink" devices as a play on "CamLink") will only do decent framerate at reasonable resolutions in MJPEG.

Quick Edit: Also, if you get one, check there's a tiny heatsink on the chip inside otherwise they cook themselves.

is there not a way to capture HDMI losslessly?

Yes, but not using that tool. Certainly not at a $8 price-point over USB 2.0 (and while some of them have USB 3.0 looking ports, they're USB 2.0 internally).

I'd start by looking at the Black Magic Intensity Pro 4K, but you're looking at hundreds of dollars.

With USB2.0 you're talking about 53MBytes/sec data rate. That's more than sufficient for lossless Full-HD video.

Yes, for anything higher quality (UHD 4K) you need more expensive hardware.

I have multiple of what I'm very confident are basically those devices. I use them fairly regularly.

They are almost all built around the MS 2109 Macrosilicon chip (and the ones that aren't are worse). They will only do MJPEG when above a certain rez and framerate.

1080p60 24-bit colour depth is 372.5MBytes/sec uncompressed. So it's going to require some compression.

I'm not an expert on h.264 etc, but can you do real-time lossless CBR below 53MBytes/sec on a readily available hardware encoder that, including the HDMI capture functionality, comes anywhere near $8?

It should be noted DOSBox uses it's own ZMBV codec for video compression which is lossless, optimized for game graphics and fast to compress in real-time during capture.

By converting to h264 the video is probably compatible with a wider range of devices, but the usual compression artifacts might appear if compression level is high.

Tangent: what's kind of freaky about the Digger video is that as a child I came to a 100% identical "optimal run" strategy for maximizing my score in the first level of digger.

Is the aspect ratio part (needing to stretch from 8:5 to 4:3) because the IBM PC didn't have square pixels?

Correct, although the nitpick is that it's not exactly the IBM PC itself, but the CGA video card output. Its resolution of 320x200 is 8:5, and so the pixels aren't square on a 4:3 CRT.

Anyone has issues with graphical glitches in DOSBox video capture? It sometimes has the wrong palette, or is just black.

I think I visit this site at least 5 times a week to copy and paste the command to generate GIF from .avi with DOSBox.

A life saver.

Why not storing them in little bash scripts e.g. in ~/bin you invoke instead?

    #!/usr/bin/env bash
    xdg-open https://susam.net/blog/good-quality-dosbox-video-capture.html

I must confess I always think of this, but then I close the browser tab and move on to something else. :) One day...

Brings back fun fond memories, bookmarked, thank you.

I loved Digger!! Thank you for this trip to the past!

Reply on news.ycombinator.com