User:Prevert/Tipos de ficheiros
Only certain file types are accepted on the Commons. These are (as of September 10, 2005):
- Images: SVG, PNG, JPEG, and XCF (GIMP), and SXD (OpenOffice.org 1.x)
- Sound: Ogg (using FLAC, Speex, or Vorbis codecs) or MIDI (with extension
- Animation: currently, only GIF is supported.
- Video: Ogg (using Theora codec)
- Text: PDF for rich text documents
- Some other OpenOffice.org 1.x formats: SXW (text), SXI (slides), SXC (spreadsheet)
If you need help with viewing or creating these formats please see Commons:Software.
Note that text articles do not belong on the Commons. Please see the Project scope for more information about what is acceptable on the Commons.
Formats not listed above must be converted to one of these before uploading. There is currently no legit way to store pristine original data for conversion to future formats or for use when patents expire.
PNG and GIF are "lossless" formats, meaning that the exact pixel colors are maintained when saving. JPEG, in contrast, is "lossy". JPEG is more appropriate for photographs; SVG (or for non-vector images, PNG) is better for drawings / diagrams, and GIF should only be used for animated images.
Unfortunately the image scaling system is still fairly bad. Currently, thumbnails are generated in the same format as the original image and are always in 24-bit color unless the image is GIF, in which case the resulting image will have 256 colors (the maximum that the GIF format allows). This means that scaling PNG images produces fairly large files even if the original image contained a palette. It also means that you currently can't upload a lossless PNG of a photo for editing and archival and then use it to make JPEG thumbnails for articles.
The Commons doesn't accept MP3 sound files. These should be converted to Ogg files and use the FLAC, Speex, or Vorbis codecs depending on your needs. Speex is intended for recordings of speech, Vorbis is for general audio and is lossy (quality is reduced) - FLAC is for general audio and is lossless (quality is preserved), but current filesize caps prevent its use for anything but short clips. In most cases, Vorbis should be used.