User:RaboKarbakian/File formatting

jpeg

The progressive setting in jpegs, I am not sure of the techoncracy of it... it has to do with the table the format uses and how small groups of pixels work together within the table. I actually saw this setting work and not work, on a slow internet. A jpeg, with the progressive setting toggled, will download into a well organized blur, first. Then continue to download into a sharp high resolution picture. Made to appear sharper for its flaws, even. The setting is very nice for the internet image collection but not so good for smaller devices.

Large, high-quality

greater than large side 600px/700px, 300ppi

For upload to commons, for taking to printer, photograph printer, etc.

quality = .92

smoothing = 0.0

progressive = True

subsmp = 0

optimize = baseline = restart = False

dct = 1

thumbnail = True

Medium, less quality

less than large side 600px/700px, 100ppi

For use on small/mobile devices like phones, e-readers

quality = .8

smoothing = 0.0

progressive = False

subsmp = 0

optimize = baseline = restart = thumbnail = False

dct = 1

FLAC

(from some how-to or man page.) Vorbis comments:

Comment encoding

Structure

The comment header logically is a list of eight-bit-clean vectors; the number of vectors is bounded to 2^32-1 and the length of each vector is limited to 2^32-1 bytes. The vector length is encoded; the vector contents themselves are not null terminated. In addition to the vector list, there is a single vector for vendor name (also 8 bit clean, length encoded in 32 bits). For example, the 1.0 release of libvorbis set the vendor string to "Xiph.Org libVorbis I 20020717".

The comment header is decoded as follows:

1) [vendor_length] = read an unsigned integer of 32 bits

2) [vendor_string] = read a UTF-8 vector as [vendor_length] octets

3) [user_comment_list_length] = read an unsigned integer of 32 bits

4) iterate [user_comment_list_length] times {

5) [length] = read an unsigned integer of 32 bits

6) this iteration's user comment = read a UTF-8 vector as [length] octets }

7) [framing_bit] = read a single bit as boolean

8) if ( [framing_bit] unset or end of packet ) then ERROR

9) done.

Content vector format

The comment vectors are structured similarly to a UNIX environment variable. That is, comment fields consist of a field name and a corresponding value and look like:

comment[0]="ARTIST=me";

comment[1]="TITLE=the sound of Vorbis";

A case-insensitive field name that may consist of ASCII 0x20 through 0x7D, 0x3D ('=') excluded. ASCII 0x41 through 0x5A inclusive (A-Z) is to be considered equivalent to ASCII 0x61 through 0x7A inclusive (a-z).

The field name is immediately followed by ASCII 0x3D ('='); this equals sign is used to terminate the field name. 0x3D is followed by the 8 bit clean UTF-8 encoded value of the field contents to the end of the field.

TITLE

Track/Work name

VERSION

The version field may be used to differentiate multiple versions of the same track title in a single collection. (e.g. remix info)

ALBUM

The collection name to which this track belongs

TRACKNUMBER

The track number of this piece if part of a specific larger collection or album

ARTIST

The artist generally considered responsible for the work. In popular music this is usually the performing band or singer. For classical music it would be the composer. For an audio book it would be the author of the original text.

PERFORMER

The artist(s) who performed the work. In classical music this would be the conductor, orchestra, soloists. In an audio book it would be the actor who did the reading. In popular music this is typically the same as the ARTIST and is omitted.

COPYRIGHT

Copyright attribution, e.g., '2001 Nobody's Band' or '1999 Jack Moffitt'

LICENSE

License information, eg, 'All Rights Reserved', 'Any Use Permitted', a URL to a license such as a Creative Commons license ("www.creativecommons.org/blahblah/license.html") or the EFF Open Audio License ('distributed under the terms of the Open Audio License. see http://www.eff.org/IP/Open_licenses/eff_oal.html for details'), etc.

ORGANIZATION

Name of the organization producing the track (i.e. the 'record label')

DESCRIPTION

A short text description of the contents

GENRE

A short text indication of music genre

DATE

Date the track was recorded

LOCATION

Location where track was recorded

CONTACT

Contact information for the creators or distributors of the track. This could be a URL, an email address, the physical address of the producing label.