filesize of captured jpg from DS-2CD2042WD-I

[badmannen]

Just realized something I find odd. ( maybe a screw loose in the head ) .. with this 4MP camera DS-2CD2042WD-I , I get a JPG file of roughly 1000kb during daytime and at night it obviously drops down alot to about 350kb.

While on my other camera which is 3MP, DS-2CD2T35 I get a daytime picture size of around 1340kb and night of about 500kb.

both are set at max resolution and max quality when capturing the pictures.
4MP - 2688 * 1520 pixel
3MP - 2048 * 1536 pixel

anyone have a good explanation ?

thanks

 

[Del Boy]

Is one black and white rather than colour?

 

[badmannen]

well the pictures at night are obviously black and white thereby the lower size for both of them during that period.

- - - Updated - - -

otherwise same dpi and bitdepth for both .

 

[pozzello]

possibly a jpeg compression setting when taking the snapshot?

check Configuration > Advanced Configuration > Storage > Snapshot
on each cam and compare.

 

[Del Boy]

Oh, I thought you meant why is night less!

It's more than likely the amount of JPG compression by the camera than anything else. I could post two files one 20MB big and one 2MB big, both jpg, both same but one compressed alot less.

Edit: What pozzello said as I clicked post!

 

[badmannen]

so the compression setting is nothing I can edit then. both are set to high.
ok maybe makes sense. the 3MP camera is FW version 5.3.3, less compression there maybe.

I got a 4MP DS-2CD3T45 with 3.3.8 FW and that one produce similar (even less ) filesize than the other 4MP DS-2CD2042WD-I . ..


whatever I give . up it does not change my life to know this I guess =D . ( My guess is that the compression ratio is chip-specific, and "high" gives pretty much the raw image then)

 

[nayr]

cant compare really against cameras, extracting JPEG's from my 4MP (2688 × 1520) Dahua feeding a 32768Kbps MJPEG stream for LPR nets me a ~500KB image in day and ~120KB image at night... thats absolute maximum quality, and they look great.

inherently they are looking at different things and compression will effect them differently, two of the exact same camera models in 2 separate environments will produce different results.