OT: Why won't this AVI play smoothly in VLC & WMP?

will-3 wrote on 6/9/2010, 12:22 PM
- This AVI video hardly plays at all in WMP.
- In VLC it plays then stops with a message at bottom right of screen that buffer is refilling to 100%

I ran gspot on the file to see what was going on and got the below...

Does anyone see anything that would make VLC or WMP choke?

And, if anyone wants to suggest another player that would be good but I still want to know why VLC in particular won't play the file smoothly.

Thanks for any help.
(Running XP Pro SP2 on Pent-4 1.8GB processor with about 1GB ram. And tried closing other apps. Oh, slowing it down to about half speed in VLC seems to work for no stuttering playback... FWIW.)

gspot report below...

Gspot shows:

FILE
File video.avi
Size 903 MB (924,820 KB / 947,015,984 bytes)

CONTAINER
File Length Correct
OpenDML (AVI v2.0)
Video: 897 MB (99.36%)
Audio: 5.72 MB (0.63%)
AVI Overhead: 57.5 KB (0.01%)

USER DATA / METADATA
[JUNK] VirtualDub build 32706/release
[ISFT] CanonMVI03

AUDIO
Codec PCM Audio
44100Hz 1411 kb/s tot (2 chnls)
No Codec Required

VIDEO
Codec: DIB (_RGB)
Name: BI_RGB Raw Bitmap
Status No Codec Required

t
Len 0:34.033
Frms 1,021
kbps 221186
Qf 24.000

Pics/s 30.000
Frames/s 30.000

d
pic (w x640x480)
sar 1.333 (4:3)
par 1.000 (1:1)
dar 1.333 (4:3)

Comments

musicvid10 wrote on 6/9/2010, 12:39 PM
Because it's uncompressed. 221Mbs. One wouldn't reasonably expect it to play at all.
will-3 wrote on 6/9/2010, 2:33 PM
I've just started using gspot and the 221k bit rate blew right by me. Thanks for pointing it out.

Wouldn't the "no codec required" reported by gspot also indicate that it was raw and not compressed?

musicvid10 wrote on 6/9/2010, 3:07 PM
Yes. It's raw RGB.
PerroneFord wrote on 6/10/2010, 8:47 AM
Uncompressed does not equal RAW. This is uncompressed. It is not RAW or VLC / WMV would not even open it.
musicvid10 wrote on 6/10/2010, 10:34 AM
I meant it in the generic (lower case adjective) usage, not as a format / codec reference (upper case).
Thanks for the clarification though. It is one that needs to be made.
will-3 wrote on 6/10/2010, 11:12 AM
What is the difference in uncompressed and raw?

- The device reads light intensity from each light sensing pixel as a binary number.
- One number for the red intensity, one for the green, and one for the blue.
- It collects those numbers from each light sensing pixel on the frame sensor.
- Now you have one frame of raw image data... the intensity of the light at each pixel in the array.

..I would call that set of data the raw data.
..It hasn't been compressed yet in any regard.
..You have in the systems memor the intensity for each red pixel, each green pixel, and each blue pixel.

I guess the first level of "compression" is chroma subsampling...

So what is the data for each set of pixels, the red, green, and blue, after it has been converted from the actual sample value to 4:x:x or whatever?

Maybe after it has been "chroma subsampled" into 4:x:x it is considered RGB... vs before "chroma subsampling" it is considered raw...???




musicvid10 wrote on 6/10/2010, 11:20 AM
Nothing to concern yourself with

Perrone is referring to the RAW (upper case) codec, which is a trademark used by Red, Cineform, and possibly a few others.

You and I are talking about raw (lower case), uncompressed RGB. That is the distinction.

In fact, if you render uncompressed RGB as MOV, it reports a format id and fourCC of 'raw'.
General

Even though uncompressed AVI reports no fourCC, the info still makes reference to 'raw RGB'
Video

For the purposes of this discussion, it might have been better not to bring it up.
PerroneFord wrote on 6/10/2010, 11:44 AM
Sorry,

I just tend to be a stickler about this because the term gets thrown around a lot and really causes confusion in some circles.

RAW sensor data has no subsampling, or any other processing done by the camera. It has no ISO, no chromatic aberration fixup, no picture profile processing, etc. Tapping the SDI or HDMI port on the camera won't give that signal to you.

"Uncompressed" on the other hand has all that baked in, likely carries audio, maybe even timecode along with it. It may be chroma subsampled on the level of cameras most of us are working with. It's as good as most of us can get from our cameras.

RAW is not a codec. In fact, it is the sensor data in absence of a codec. RED, Cineform, ARRI, Grass Valley (Viper), Panavision, and others all have their versions of it.

And musicvid, I am cool with the idea of "RAW" vs "raw". Just wanted to be on the same page...
musicvid10 wrote on 6/10/2010, 11:50 AM
I am cool with the idea of "RAW" vs "raw". Just wanted to be on the same page...

Me too. We both know that despite all the "raw" enthusiasm, Will occasionally tends to overthink new concepts. That's why I wanted to keep it in the vernacular. But as I already stated, your point is well taken.