streaming : frame rate & compression

[mathmax]

Hello

I have two files of the same video.. they were captured on a streaming source at two different moments. But when I compare the videos, it seems that the frames don't match exactly.
First the frame rate seems to differ between the two files.. but also for each file, the frame rate don't seem to be constant in time... is it possible that that the stream skip some images? But if the frame rate isn't constant in time, I guess the file format needs to adjust the flow... how does it work exactly? When I scroll the images, I can clearly see that some images are in one version but not on the other. So it seems that either some image were skiped or they were "interpolated" from the original images to create a flow with a lower frame rate...
Also, it seems that the quality differ sometimes because of the encoding... I guess that depending on the connection state, the encoding is more or less strong...
I really don't know well about how streaming words for both the compression and the frame rate...

Thank you in advance for any explanations you can give regarding this issue

[aedipuss]

sounds like vfr which can be used, but makes the video pretty useless for anything other than a quick viewing. bitrate has to do with the compression and it can also be cbr or vbr. constant or variable bit rate.

http://en.wikipedia.org/wiki/Variable_frame_rate

[mathmax]

Thank you for the answer

The files are FLV containing:
- a h.264 file
- a .aac file
- a .txt file in which it is written:

# timecode format v2
0
0
0
73
173
206
306
373
439
506
573
639
...

is the timecode file used for variable frame rate? If I import all the frame to virtualdub, can I use the timecode file to export with the same variable frame rate?

Also i still don't understand if a frame of the flv correspond to a single frame of the original file (before broadcasting) or if it is the result of an interpolation of several frames of the original file. In other words, does the vbr process only skip some images or does it "gather" some images?

As a final question, I wonder if it's possible to gather the two files (and their timecodes eventually) to get a single file with more frames. This would allow me to have a more fluid video..