Author Archives: Multimedia Mike

Using gcovr with FFmpeg

When I started investigating code coverage tools to analyze FFmpeg, I knew there had to be an easier way to do what I was trying to do (obtain code coverage statistics on a macro level for the entire project). I was hoping there was a way to ask the GNU gcov tool to do this directly. John K informed me in the comments of a tool called gcovr. Like my tool from the previous post, gcovr is a Python script that aggregates data collected by gcov. gcovr proves to be a little more competent than my tool.

Results
Here is the spreadsheet of results, reflecting FATE code coverage as of this writing. All FFmpeg source files are on the same sheet this time, including header files, sorted by percent covered (ascending), then total lines (descending).

Methodology
I wasn’t easily able to work with the default output from the gcovr tool. So I modified it into a tool called gcovr-csv which creates data that spreadsheets can digest more easily.

  • Build FFmpeg using the '-fprofile-arcs -ftest-coverage' in both the extra cflags and extra ldflags configuration options
  • 'make'
  • 'make fate'
  • From build directory: 'gcovr-csv > output.csv'
  • Massage the data a bit, deleting information about system header files (assuming you don’t care how much of /usr/include/stdlib.h is covered — 66%, BTW)

Leftovers
I became aware of some spreadsheet limitations thanks to this tool: Continue reading →

Bye Bye FATE Machine

This is the computer that performed the lion’s share of FATE cycles for the past 1.5 years before Mans put a new continuous integration system into service. I’ve now decided to let the machine go. I can’t get over how odd this feels since this thing is technically the best machine I own.



It’s a small form factor Shuttle PC (SD37P2 v2); Core 2 Duo 2.13 GHz; 2 GB RAM; 400 GB SATA HD; equipped with the only consistently functional optical drive in my house (uh oh). I used it as my primary desktop from March 2007 – November 2008, at which point I repurposed it for FATE cycles.

As mentioned, the craziest part is that this is technically the best computer in my house. My new EeePC 1201PN isn’t at quite the same level; my old EeePC can’t touch it, of course; the Mac Mini has a little more RAM but doesn’t stack up in nearly all other areas. But the Shuttle just isn’t seeing that much use since the usurpation. I had it running automated backup duty for multimedia.cx but that’s easy enough to move to another, lower-powered system.

Maybe the prognosticators are correct and the PC industry has matured to the point where raw computing power simply doesn’t matter anymore. I fancy myself as someone who knows how to put CPU power to work but even I don’t know what to do with the computing capacity I purchased over 3 years ago.

Where will the Shuttle go? A good home, I trust– I know a family that just arrived in the country and could use a computer.

Linux Media Player Survey Circa 2001

Here’s a document I scavenged from my archives. It was dated September 1, 2001 and I now publish it 9 years later. It serves as sort of a time capsule for the state of media player programs at the time. Looking back on this list, I can’t understand why I couldn’t find MPlayer while I was conducting this survey, especially since MPlayer is the project I eventually started to work for a few months after writing this piece.

For a little context, I had been studying multimedia concepts and tech for a year and was itching to get my hands dirty with practical multimedia coding. But I wanted to tackle what I perceived as unsolved problems– like playback of proprietary codecs. I didn’t want to have to build a new media playback framework just to start working on my problems. So I surveyed the players available to see which ones I could plug into and use as a testbed for implementing new decoders.

Regarding Real Player, I wrote: “We’re trying to move away from the proprietary, closed-source ‘solutions'”. Heh. Was I really an insufferable open source idealist back in the day?

Anyway, here’s the text with some Where are they now? commentary [in brackets]:

Towards an All-Inclusive Media Playing Solution for Linux

I don’t feel that the media playing solutions for Linux set their sights high enough, even though they do tend to be quite ambitious. Continue reading →

2 GB Should Be Enough For Me

My new EeePC 1201PN netbook has 2 GB of RAM. Call me shortsighted but I feel like “that ought to be enough for me”. I’m not trying to claim that it ought to be enough for everyone. I am, however, questioning the utility of swap space for those skilled in the art of computing.



Technology marches on: This ancient 128 MB RAM module is larger than my digital camera’s battery charger… and I just realized that comparison doesn’t make any sense

Does anyone else have this issue? It has gotten to the point where I deliberately disable swap partitions on Linux desktops I’m using ('swapoff -a'), and try not to allocate a swap partition during install time. I’m encountering Linux installers that seem to be making it tougher to do this, essentially pleading with you to create a swap partition– “Seriously, you might need 8 total gigabytes of virtual memory one day.” I’m of the opinion that if 2 GB of physical memory isn’t enough for my normal operation, I might need to re-examine my processes.

In the course of my normal computer usage (which is definitely not normal by the standard of a normal computer user), swap space is just another way for the software to screw things up behind the scenes. In this case, the mistake is performance-related as the software makes poor decisions about what needs to be kept in RAM.

And then there are the netbook-oriented Linux distributions that insisted upon setting aside as swap 1/2 gigabyte of the already constrained 4 gigabytes of my Eee PC 701’s on-board flash memory, never offering the choice to opt out of swap space during installation. Earmarking flash memory for swap space is generally regarded as exceptionally poor form. To be fair, I don’t know that SSD has been all that prevalent in netbooks since the very earliest units in the netbook epoch.

Am I alone in this? Does anyone else prefer to keep all of their memory physical in this day and age?