png or jpeg

rdr1jlr3 wrote on 1/17/2017, 12:21 PM

Which photo file is better? I have always used jpeg, however, I am using photos from a third party and their scanner creates both file types and the png files are 10x bigger - to me that means greater resolution. to test this, I have uploaded the png files into a video project without any problems, however, I am wondering if I might encounter problems later as I add features etc. Anyone have experience with this??

Comments

emmrecs wrote on 1/17/2017, 1:33 PM

Better for what? Yes .png files will be a larger size than .jpg, partly because the png specification requires more data to be saved. (One part of this is that 32 bit .png files allow transparency, so one can use e.g. the image of a person from which the original background has been removed/made transparent.) Higher resolution? Possibly, if the png files have a higher dpi figure for the scans.

Normally, png files would be recommended over jpgs if one were using images on a web site where the viewer's browser might cause the image to appear "smaller" or "larger" than the creator intended. For video projects, I doubt that there would be very much, if any, visually perceptible difference between the two types when viewed as e.g. the background.

As to whether the use of png files might cause you to "encounter problems later", I think the only possible issue might be that the extra size of those png images would use more RAM when they are loaded into a video project. This could create problems if you are running a lowish-spec computer and/or you have limited RAM.

Jeff

yvon-robert wrote on 1/17/2017, 4:12 PM

Hi,

If you use a scan at 120 dpi, may be 4 x 6 inches, 24 bits this is the same to use either jpg or png. But if you use a scan and output png in 32 bits you can use a transparent background the only advantage transparency the size today is not important because jpg is a compressed format it load faster but computer must decompresse the file, png is not compressed take more time to load but no decompression.

Regards,

johnebaker wrote on 1/18/2017, 8:22 AM

@ YR

. . . . png is not compressed . . . .

PNG is a compressed file, however the compression engine is a lossless one similar to the Deflate option used in Winzip, 7zip and other compressors.

Inflating a png file may not be so processor intensive as a jpeg - however this does depend on the compression factor used in the jpg.

To answer the OP's question - it all depends on what you require of the images - using jpg 's can be just as good as using png images if the compression factor in the jpg is not to high, however you do not have the transparency option with jpg's which is available in png files.

In addition the resolution, ie pixel dimensions of the image, must be at minimum the same as the highest resolution output from MEP eg if you intend to export UHD at 3840*2160 then your image should be at least the same resolution or higher.

. . . . scan at 120 dpi . . .

DPI refers to to the number of ink dots per image an image is printed at, and is a misused term for the pixels per inch (PPI) a digital scanner will scan an image at.

In general the term resolution is better as this describes the actual number of pixels horizontally and vertically an image has.

HTH

John EB

rdr1jlr3 wrote on 1/18/2017, 9:17 AM

Thanks John EB - so what is your recommendation if I am creating a MEP video from still photos ( probably 200-300 photos, about 20 minutes of playing time). jpeg file size is 1000kb and same png file is 2000 kb.

johnebaker wrote on 1/18/2017, 10:30 AM

That is actually a difficult question to answer if you already have the photos in both formats on your hard drive.

Assuming the following:

image transparency is not required
the original image source is a digital camera
the images are not RAW files - although MEP does support certain RAW formats

then they are most likely to be jpg and are the highest quality possible so I would say use the original images.

Any reprocessing, to for example png, is not going to improve the quality.

HTH

John EB