PapaJohn Productions

Newsletter #161 - Aug 4,2007
Codecs and GSpot...
I've been using and mentioning GSpot pretty often lately. The latest version 2.70a, released in
February, runs on Vista in addition to XP, started to support WMV and MOV files, and extended its MP4 support.
GSpot is the best general purpose tool to:
The checking doesn't stop with providing properties or a list. The utility includes a built-in mini player that shows the results of using the selected codecs.
On the other hand, it's bitten off a lot and needs to chew on things a bit more before it's a comfortable and usable tool for most. I'm still scratching my head trying to understand most of what it tells me.

I'm an experienced user and hacker, but not a programmer. I understand the basic concepts of file compression and can move files around from one software app to another to achieve something. But I have a long way to go to understand such things as fourcc code, and now there's the ftyp code for MP4 files. 
What's an "ftyp"?
... from the GSpot website...

An ftyp is a four letter code (sometime including blanks) that is used to identify the "type" of encoding used, the "compatibility", or the "intended usage" of a media file. It only pertains to MP4 or newer QuickTime (.mov) container file formats. It is somewhat analogous to the so-called fourcc code, used for a similar purpose for media embedded in the AVI container format.

The four letter code "ftyp" itself is the atom type (in QuickTime terminology) or box type (in MP4 terminology). An atom/box with this label contains data comprised of certain identifier(s). The table created for this website is an attempt to compile a list of all such identifiers one might find.

While there are many sites with comprehensive lists of AVI fourcc codes, I have found no satisfactory listing of ftyp codes. Because I needed such a list to improve the MP4 support of my GSpot application, I compiled a list myself from websites, specifications, samples, and helpful information from other contributors. The original and main intent of compiling the data was (and still is) to incorporate into GSpot's external database file. But while I was at it, I decided to create this webpage as well, since there really does seem to be a need for one.

Yes, the subject of codecs gets more complex as time goes by, increasing the need for a tool such as GSpot. I appreciate very much his pulling together all this info about codecs and filters, and providing GSpot as a free to use utility.
For this newsletter, I'll skim over what GSpot provides. Before getting into details, here's...
... a couple notes...

With over 100 videos on YouTube, my most viewed one is a 2-1/2 minute Father-Daughter Dance at a traditional wedding.  It's not far out, not wild, not R-rated... just a classic wedding dance which lately is being viewed about 18 times a day.
It has no star rating and no comments... just views. I can only assume the clip is helpful to some movie makers working on editing their wedding videos.
I mentioned my first 3 software reviews on last week... this week the site moved into its official alpha stage with the URL of It has a bit to pull together yet before it's ready for prime time, but it'll get there.
.... back to the main topic...

... is developing nicely. I'll go over it's main features, starting with...
checking a multimedia file's (video, audio, pictures) properties
This feature is the one of most help to me... checking a file to see if it will play OK on the computer being used, and getting clues about why a source file isn't importing or working in a project.
I selected 6 assorted video clips, opened them in GSpot, took screen shots, and annotated them to point out some of the things I look at when assessing a file.

WMV Photo Story 3 - standard 320x240
If I hadn't made it myself with Photo Story 3, I'd have a hard time determining what the file was from this info. The WVP2 video codec isn't in the list of installed codecs and filters, and it's codec status is undetermined to GSpot. As the opening paragraph says, this version of GSpot has only begun to support WMV files.
I found WVP2 as a line item in GSpot's list of media types found in the registry, a feature I only use when writing a newsletter.

WMV movie from MM2.1 - widescreen 856x480
This one's a bit easier. The WMV3 file format is in GSpot's list of all codecs and filters. The clues all point to it being a Windows Media Video file. 
As for the Photo Story, the codec status isn't determined yet. But what info is provided is accurate.  

MPEG2 file... this one a SVCD (Super VCD) made by TMPGEnc... 480x480 pixels
Note the metadata telling you the software app and version I used to make the file... and the info at the lower right includes the SVCD label being bold... versus the other choices of VCD or DVD labels.
Important to converting MPEG files is understanding the audio stream. In this file, it's an MPEG-1 layer 2 stream (MP2).

AVI - Motion JPEG file from a Canon Hard Drive TX-1 Camcorder- widescreen High Definition 1280x720
This is an interesting one as it's an AVI file compressed with a motion jpeg codec, and it's high definition. I got into it to help someone wrestling with getting clips into Movie Maker from a new Canon TX-1 camcorder. He didn't have the codec, and I did. What was impossible for him was easy for me.
I used MM2.1 as the conversion utility, saving it using a custom profile to preserve the 1280x720 size. He sent an AVI file and I returned a WMV.

DV-AVI type I standard aspect ratio... made by MM2.1
This file is a full hour tape from my mini-DV camcorder, captured using MM2.1.
The audio codec info isn't shown, as the type I DV file type doesn't have the second audio stream like the type II DV-AVI has. You know the audio is there because you can hear it... it's just wrapped up with the video track so the properties are not picked up by GSpot.
DV-AVI type I

DV-AVI type II... made by VirtualDub compressing it with the Panasonic DV Codec
The audio info of GSpot is a good clue that it's a type II DV-AVI file... the 2nd line of info in the Container area is an even better clue.
The metadata includes the software and version used to make the file.

the next major feature of GSpot is to...
check your computer to see what codecs it has...
Open - XPMy older HP laptop is a high end system with the Media Center Edition of XP on it... it has collected lots of codecs as software was added over time.
When GSpot opens, it routinely checks the codecs and says 'Ready' when it's time to start using it. It says my XP system has 447 codecs loaded.
Vista - 447My new Toshiba laptop is a low end system with the Home Basic version of Vista on it, not used long enough to have collected as many codecs. When GSpot is ready, it says there are 169 video codecs loaded.
Many codecs come pre-loaded on a computer. Others come and go with associated software... I don't try to keep tabs of them. I only dig into them when I try to open a file and find I don't have a needed codec, or my software or system is crashing because of codec issues....
The list of all codecs and filters is first sorted by 'Type'... all of the codecs listed being first classified into one of five types. I'll skip over the first 4 types and spend more time on the last one.
  • A handful of ACM line items all point to ID's of msacm.xxxxx... in the quartz.dll file, the Microsoft Audio Compression Manager. There are 15 of them on my XP and 8 on Vista.
  • DMO type... input uncompressed media data and the DMO delivers compressed media data.  10 of them are on my XP and Vista systems, and they all point to the qasf.dll library file.
  • Most of the listed items fall into the DSH (Direct Show) type. They include the audio codecs, the families of those for MPEG videos, Real files, Divx and Xvid, Motion JPEG. 
  • The REND type accounts for 33 on my XP and 15 on Vista. They all have something to do with things like rendering, outputting, muxing, or synthesizing... geekie words for making things. Of note, the Midi output device and wave table synthesizer are in this group.
  • The last type is VFW (Video for Windows), with 23 on my XP system and 5 on Vista. Let's look at the lists of items.
VFW for XP
VirtualDub FiltersThe list reminds me of what I see when using VirtualDub or TMPGEnc to work on or do a conversion to an AVI file.
The list at the left shows the VFW types listed by GSpot on my XP laptop.
The list at the right shows the video compression choices in the picklist of VirtualDub. It's the same list.
The VFW files include AVI and WMV, files we are familiar with and maybe most comfortable with when doing video editing.
VFW for Vista
The VFW type stands out as the one with the largest difference in the number of items on my XP and Vista systems. The list above was on the XP... the short list at the right is the five of them on the Vista system. 
I checked the five VFW codecs on the Vista laptop by opening the high-def (1280x720) Motion JPEG AVI file from the Canon TX1 hard drive camcorder, using VirtualDub. I rendered it to new files using each of the codecs.
  • The Cinepak codec worked fine and took its usual long time, as it has to do lots of compressing
  • Intel 1420 IYUV did it in a few seconds... and gave a big file
  • Intel IYUV also did it in a few seconds... another big file
  • The Microsoft RLE codec gave an error message about the source image format not being acceptable
  • Microsoft Video 1 did it about as quickly as the Intel codecs, and the file was about as large
Microsoft RLE Filter Details

To see why VirtualDub returned the error for the Microsoft RLE codec, I did an online search and found a post that said...
.... the MS RLE codec will only accept 8-bit colormapped images, and there is absolutely no way to create such a sequence with VirtualDub....
Maybe not, so I added VirtualDub's greyscale filter to rip the color from the clip, and the codec worked fine. I ended up with a nice looking black and white video. It also saved the new file very quickly.

I couldn't resist taking a look at the VFW filter type list on my desktop Vista Ultimate system... it has a few more than the laptop with Home Basic.
  • the Panasonic DV codec
  • Zoran Decompressor
  • PCLEPIM1 32 bit Compressor
  • PCLEPIXL 32 bit Compressor  
I usually add the Panasonic DV codec, and surprised I didn't already put it on the new laptop. The others seem to be from installing the Dazzle80 video capture device driver to test it under Vista.

On to another feature of GSpot...
what media types are listed in the registry?
Registry InfoI'm not advanced enough in the subject of codecs to get much out of this info. Maybe someday!!!
All I can say is that you get to this list via System > List Media Types...
Maybe there's something more in the info you get by right-clicking on one... let's check the WMV3 one.
The options to list all filters accepting or producing this format are long, and still not of any practical value to me, but we'll take a look at what's in such lists.

which of your codecs are capable of making or playing a media type?
With that right click on the above list... using WMV3 as the line item... you get a list of the filters that accept the item as an input, or those that produce it as an output.
Good info for programmers, but beyond the needs of most users.
WMV3-Inputs and Outputs
That finishes the run-though of the main features of GSpot.
One thing I didn't do was run any of the dynamic checks that GSpot offers as it tests the Microsoft and non-Microsoft options to play a file, viewing it in its little embedded media player.

Conclusion and Closing... and What's Next?
There's no conclusion. More codecs will go into my system over the upcoming months and years... and GSpot info will be more complete for lots of file types.
And we have the flood of new MP4 codecs and 'ftyp' type codecs and filters to learn about. 
Have a great week and enjoy your summer fun and video work...