Add documentation regarding supported by vcmi formats

docs/modders/File_Formats.md

@@ -0,0 +1,80 @@
+# File Formats
+
+This page describes which file formats are supported by vcmi. 
+
+In most cases, VCMI supports formats that were supported by Heroes III, with addition of new formats that are more convenient to use without specialized tools. See categories below for more details on specific formats
+
+### Images
+
+For images VCMI supports:
+- png. Recommended for usage in mods
+- bmp. While this format is supported, bmp images have no compressions leading to large file sizes
+- pcx (h3 version). Note that this is format that is specific to Heroes III and has nothing in common with widely known .pcx format. Files in this format generally can only be found inside of .lod archive of Heroes III and are usually extracted as .bmp files
+
+Transparency support:
+VCMI supports transparency (alpha) channel, both in png and in bmp images. There may be cases where transparency is not fully supported. If you discover such cases, please report them.
+
+For performance reasons, please use alpha channel only in places where transparency is actually required and remove alpha channel from image othervice
+
+Palette support:
+TODO: describe how palettes work in vcmi
+
+### Animations
+
+For animations VCMI supports .def format from Heroes III as well as alternative json-based. See [Animation Format](Animation_Format.md) for more details
+
+### Sounds
+
+For sounds VCMI currently requires .wav format. Generally, VCMI will support any .wav parameters, however you might want to use high-bitrate versions, such as 44100 Hz or 48000 Hz, 32 bit, 1 or 2 channels
+
+Support for additional formats, such as ogg/vorbis and ogg/opus is likely to be added in future
+
+### Music
+
+For sounds VCMI currently requires .mp3 format. Support for additional formats, such as ogg/vorbis and ogg/opus is likely to be added in future
+
+### Video
+
+Starting from VCMI 1.6, following video container formats are supported by VCMI:
+
+- .bik - one of the formats used by Heroes III
+- .smk - one of the formats used by Heroes III. Note that these videos generally have lower quality and are only used as fallback if no other formats are found
+- .ogv - format used by Heroes III: HD Edition
+- .webm - modern, free format that is recommended for modding.
+
+Supported video codecs:
+- bink and smacker - formats used by Heroes III, should be used only to avoid re-encoding
+- theora - used by Heroes III: HD Edition
+- vp8 - modern format with way better compression compared to formats used by Heroes III
+- vp9 - recommended, this format is improvement of vp9 format and should be used as a default option
+
+Support for av1 video codec is likely to be added in future.
+
+Supported audio codecs:
+- binkaudio and smackaud - formats used by Heroes III
+- vorbis - modern format with good compression level
+- opus - recommended, improvement over vorbis. Any bitrate is supported, with 128 kbit probably being the best option
+
+### Json
+
+For most of configuration files, VCMI uses [JSON format](http://en.wikipedia.org/wiki/Json) with some extensions from [JSON5](https://spec.json5.org/) format, such as comments.
+
+### Maps
+
+TODO: describe
+
+### Campaigns
+
+TODO: describe
+
+### Map Templates
+
+TODO: describe
+
+### Archives
+
+TODO: describe
+
+### Txt
+
+TODO: describe

docs/modders/Readme.md

@@ -19,8 +19,10 @@ Example of how directory structure of your mod may look like:
                 music/   - music files. Mp3 and ogg/vorbis are supported
                 sounds/  - sound files, in wav format.
                 sprites/ - animation, image sets (H3 .def files or VCMI .json files)
-                video/   - video files, .bik or .smk
+                video/   - video files, .bik, .smk, .ogv .webm
 ```
+See [File Formats](File_Formats.md) page for more information on which formats are supported or recommended for vcmi
+
 
 ## Creating mod file