Compress/encode video recorded by photo camera

[trynitro]

Hi,

I have been trying for some time now to compress some videos that I have recorded using a photo camera (Canon SD870IS). Every time I tried either the video was bad or the sound was bad. I have searched the tutorials, but I did not find an article that fitted my problem or maybe I didn't realize that those were helpful.

All I wanted was to keep the quality but decrease the file size - if that is possible. Could you please recommend an application or some tutorial that could help me decrease the file size?

Thank you,
Lucian


This is the media info from one of the files:
General
Complete name : D:\Poze\munte\MVI_0833.AVI
Format : AVI
Format/Info : Audio Video Interleave
File size : 85.5 MiB
Duration : 45s 367ms
Overall bit rate : 15.8 Mbps
Mastered date : Thu Aug 28 13:32:10 2008
Writing application : CanonMVI06

Video
ID : 0
Format : M-JPEG
Frame mode : 8
Codec ID : MJPG
Duration : 45s 367ms
Bit rate : 15.1 Mbps
Width : 640 pixels
Height : 480 pixels
Display aspect ratio : 4:3
Frame rate : 30.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Scan type : Progressive
Bits/(Pixel*Frame) : 1.639
Stream size : 81.7 MiB (96%)

Audio
Format : PCM
Format settings, Endianness : Little
Format settings, Sign : Unsigned
Codec ID : 1
Codec ID/Hint : Microsoft
Duration : 45s 367ms
Bit rate mode : Constant
Bit rate : 705.6 Kbps
Channel(s) : 1 channel
Sampling rate : 44.1 KHz
Bit depth : 16 bits
Stream size : 3.82 MiB (4%)
Interleave, duration : 986 ms (29.59 video frames)
Interleave, preload duration : 1000 ms

[davexnet]

Try AVIDemux.

[edDV]

You have 640x480 MJPEG frames at 30fps.

Windows Movie Maker can edit it and convert to wmv so long as you have an MJPEG codec installed.

[trynitro]

I tried Windows Movie Maker and with it the encoded movie looses a lot of quality when comparing with the original.
I will give AVIDemux a try too.

I searched the site some more and I found HandBrake which seems to do a good job. Do you think that is a good solution for what I need?


thank you for your suggestions

[jagabo]

Quality will depend largely on what codec you select and how much you ask it to compress.

[edDV]

Keep in mind that digital camera MJPEG is heavily intrafreame compressed (~50x) and noisy. Audio is uncompressed low grade 8 or 12 bit PCM mono.

If you want to compress further some intraframe (Mpeg GOP based) compression may be possible but the noise will make motion detection tricky. Best to use a denoise filter before re-compression. Audio can be compressed to mp2 or ac3.

[trynitro]

@edDV: Although what you are saying sounds good, I do not really know how to translate that into facts.
What you are recommending is to decompress the file using a denoise filter, then compress it back and at re-compression use a mp2-ac3 audio codec, right?
Could you also tell me what applications could help me do that?


Thanks a lot to all of you!! I really appreciate all the help

[jagabo]

Oops, wrong thread.

[Gavino]

Keep in mind that digital camera MJPEG is heavily intrafreame compressed (~50x) and noisy. Audio is uncompressed low grade 8 or 12 bit PCM mono.

According to his first post, trynitro's video has a bitrate of 15.1Mbps, with Bits/(Pixel*Frame) = 1.639.
By my calculations, that's a compression of less than 8x.
Audio is 16 bit mono.

[jagabo]

I agree with Gavino -- if you assume the source is 4:2:0 then it's less than 8x compression:

640 x 480 * 1.5 (bytes per pixel, 4:2:0) * 30 fps * 8 (bits per byte) / 15,000,000 = ~7.37

Probably pretty good quality. MPEG 2 or h.264 compression should do pretty well with that unless it's very noisy.

[Gavino]

if you assume the source is 4:2:0 ...

That's what I assumed, since it's what the MediaInfo listing reports.

[edDV]

I was responding to the typical digital camera using MJPEG for video. MJPEG has been a digital camera shortcut to video using frame based JPEG compression only. This meant they had to over-compress intraframe (no interframe compression). Audio was uncompressed 8 bit PCM (lowest common denominator). I guess they were avoiding MPeg or AC3 patents.

These newer cams seem to be using higher 15 Mb/s bit rates (thanks to AVCHD pushing flash ram to Level 4-6) and audio is now 16 bit PCM mono. That gives you more usable video bitrate to apply interframe MPeg GOP based compression (MPeg2 or MPeg4 based).

A camera that captures direct to MPeg (e.g. AVC h.264) will have higher quality per bitrate.