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Screencasting Under Linux--A brief Story

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My first consideration for making A/V screencasts under Linux is Software. What programs are available to do screen-recordings with simultaneous audio narration under Linux? I've probably tried them all: recordmydesktop (which has both gtk-recordmydesktop and qt-recordmydesktop GUI font ends), Istanbul, xvidcap, and wink. Frankly, none of these yielded the high-quality screen capture I wanted. But the real problem is that the audio quality was worse. After thrashing about, I finally end up with a non open source commercial product called DemoRecorder.

Now DemoRecorder is a commercial, proprietary program, which costs $47.00US, $77.00US, or $247.00US depending on the desired feature set. I purchased the $77.00 license. This does not work under Mandriva 2010 in nested desktop mode, but the openGL mode of capture works well. No dropped frames on the video side, and relativey smooth modion. On the audio side, no major sound glitches like I had with recordmydesktop.

Using DemoRecorder in the openGL mode is a two-phase process--Running the demorec --opengl program to perform the initial capture of the video and audio files, then the transcoding or assembly into a finished product using demorec-to-avi (or demorec-to-dv, demorec-to-flv, demorec-to-mpeg1, demorec-to-mpeg2, demorec-to-ogg-theora or whatever video codec/container you wish).

While the sound quality is considerably improved, it's still a bit hollow and tinny when recorded from my Logitech headset. I found the captured sound file produced by demorecorder, which I could then import into Audacity in raw format. I could then edit and improve the sound in Audacity, and export the edited sound file back to the drive before the assembly/transcoding of the video files and the sound file into one avi file.

This works--still, the sound isn't quite professional quality, but close. The real issue with this is that this type of post-production sound-editing takes a lot of time. Better, if possible, to get a high-quality sound recording to begin with, and bypass the editing step. Time for some research into sound production.

I have no experience in sound recording--I'm a computer guy, but I do like to play with hardware.
Fortunately, I already have a really good high-quality sound card in my working desktop computer--an HT Omega Claro Plus.

Turns out, you can get a decent quality mic, and a device called a sound mixer, and you can record really great sound. Good to know. I end up purchasing a Behringer XENYX 1204FX model mixer for $179.99US. This model of mixer turns out to be overkill on my part, and I now know I could have got by just fine with a cheaper mixer (prices for a mixer can range from $99.00US to several thousand US dollars).

As is often the case, one purchase often begets another. So, on to buy a decent, but relatively inexpensive condensor mike (after shelling out too many $$$ on the mixer). I end up purchasing an MXL 990 condenser microphone with a shock mount for $49.00US. Then a proLine desktop mic stand, model MS112 ($29.99US). Finally, I purchase assorted cables and adapters.

After all my sound gear arrives, I connect the mic to my mixer, the mixer to my sound card. Then I fire up Audacity to run some tests. After fiddling with the gear for about an hour, I'm amazed at the quality of the sound captures. Now I can start recording those educational screencasts in earnest.

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Games for GNU/Linux

  • Why GNU/Linux ports can be less performant, a more in-depth answer
    When it comes to data handling, or rather data manipulation, different APIs can perform it in different ways. In one, you might simply be able to modify some memory and all is ok. In another, you might have to point to a copy and say "use that when you can instead and free the original then". This is not a one way is better than the other discussion - it's important only that they require different methods of handling it. Actually, OpenGL can have a lot of different methods, and knowing the "best" way for a particular scenario takes some experience to get right. When dealing with porting a game across though, there may not be a lot of options: the engine does things a certain way, so that way has to be faked if there's no exact translation. Guess what? That can affect OpenGL state, and require re-validation of an entire rendering pipeline, stalling command submission to the GPU, a.k.a less performance than the original game. It's again not really feasible to rip apart an entire game engine and redesign it just for that: take the performance hit and carry on. Note that some decisions are based around _porting_ a game. If one could design from the ground up with OpenGL, then OpenGL would likely give better performance...but it might also be more difficult to develop and test for. So there's a bit of a trade-off there, and most developers are probably going to be concerned with getting it running on Windows first, GNU/Linux second. This includes engine developers.
  • Why Linux games often perform worse than on Windows
    Drivers on Windows are tweaked rather often for specific games. You often see a "Game Ready" (or whatever term they use now) driver from Nvidia and AMD where they often state "increased performance in x game by x%". This happens for most major game releases on Windows. Nvidia and AMD have teams of people to specifically tweak the drivers for games on Windows. Looking at Nvidia specifically, in the last three months they have released six new drivers to improve performance in specific games.
  • Thoughts on 'Stellaris' with the 'Leviathans Story Pack' and latest patch, a better game that still needs work
  • Linux community has been sending their love to Feral Interactive & Aspyr Media
    This is awesome to see, people in the community have sent both Feral Interactive & Aspyr Media some little care packages full of treats. Since Aspyr Media have yet to bring us the new Civilization game, it looks like Linux users have been guilt-tripping the porters into speeding up, or just sending them into a sugar coma.
  • Feral Interactive's Linux ports may come with Vulkan sooner than we thought
  • Using Nvidia's NVENC with OBS Studio makes Linux game recording really great
    I had been meaning to try out Nvidia's NVENC for a while, but I never really bothered as I didn't think it would make such a drastic difference in recording gaming videos, but wow does it ever! I was trying to record a game recently and all other methods I tried made the game performance utterly dive, making it impossible to record it. So I asked for advice and eventually came to this way.

Leftovers: Software

  • DocKnot 1.00
    I'm a bit of a perfectionist about package documentation, and I'm also a huge fan of consistency. As I've slowly accumulated more open source software packages (alas, fewer new ones these days since I have less day-job time to work on them), I've developed a standard format for package documentation files, particularly the README in the package and the web pages I publish. I've iterated on these, tweaking them and messing with them, trying to incorporate all my accumulated wisdom about what information people need.
  • Shotwell moving along
    A new feature that was included is a contrast slider in the enhancement tool, moving on with integrating patches hanging around on Bugzilla for quite some time.
  • GObject and SVG
    GSVG is a project to provide a GObject API, using Vala. It has almost all, with some complementary, interfaces from W3C SVG 1.1 specification. GSVG is LGPL library. It will use GXml as XML engine. SVG 1.1 DOM interfaces relays on W3C DOM, then using GXml is a natural choice. SVG is XML and its DOM interfaces, requires to use Object’s properties and be able to add child DOM Elements; then, we need a new set of classes.
  • LibreOffice 5.1.6 Office Suite Released for Enterprise Deployments with 68 Fixes
    Today, October 27, 2016, we've been informed by The Document Foundation about the general availability of the sixth maintenance update to the LibreOffice 5.1 open-source and cross-platform office suite. You're reading that right, LibreOffice 5.1 got a new update not the current stable LibreOffice 5.2 branch, as The Document Foundation is known to maintain at least to versions of its popular office suite, one that is very well tested and can be used for enterprise deployments and another one that offers the latest technologies.