Update file format docs

Author: joto

_file_formats_manual/03_formats.md

@@ -156,16 +156,17 @@ description, even if the file name has the correct suffix.
 
 Here is a list of optional settings currently supported:
 
-| Format        | Option               | Default | Description
-| ------        | ------               | ------- | -----------
-| PBF           | `pbf_dense_nodes`    | true    | Use DenseNodes (more space efficient)
-| PBF           | `pbf_compression`    | gzip    | Compress blocks using gzip (use "none" to disable)
-| XML           | `xml_change_format`  | false   | Set change format, can also be set by using `osc` instead of `osm` suffix
-| XML           | `force_visible_flag` | false   | Write out `visible` flag on each object, also set if `osh` instead of `osm` suffix used
-| *all*         | `add_metadata`       | true    | *see below*
-| PBF, XML, OPL | `locations_on_ways`  | false   | Add node locations to way nodes (libosmium-specific extension)
-| DEBUG         | `use_color`          | false   | Output with ANSI colors
-| DEBUG         | `add_crc32`          | false   | Add CRC32 checksum to all objects
+| Format        | Option                  | Default | Description
+| ------        | ------                  | ------- | -----------
+| PBF           | `pbf_dense_nodes`       | true    | Use DenseNodes (more space efficient)
+| PBF           | `pbf_compression`       | zlib    | Compression for PBF blocks (`none`, `zlib`, `lz4`)
+| PBF           | `pbf_compression_level` |         | Compression level for PBF blobs
+| XML           | `xml_change_format`     | false   | Set change format, can also be set by using `osc` instead of `osm` suffix
+| XML           | `force_visible_flag`    | false   | Write out `visible` flag on each object, also set if `osh` instead of `osm` suffix used
+| *all*         | `add_metadata`          | true    | *see below*
+| PBF, XML, OPL | `locations_on_ways`     | false   | Add node locations to way nodes (libosmium-specific extension)
+| DEBUG         | `use_color`             | false   | Output with ANSI colors
+| DEBUG         | `add_crc32`             | false   | Add CRC32 checksum to all objects
 
 ### Writing metadata on OSM objects (`add_metadata`)
 

_file_formats_manual/05_pbf.md

@@ -17,11 +17,27 @@ Osmium usually will compress PBF blocks using zlib. To disable this, use the
 format parameter `pbf_compression=none`. This makes reading and writing faster,
 but the resulting files are larger.
 
+From Libosmium 2.16, the compression type LZ4 is also supported
+(`pbf_compression=lz4`). Compression and decompression with LZ4 is much faster
+than with zlib, but the compression ratio is not quite as good. Note that LZ4
+compression is optional and only available if it was compiled in. Most other
+programs reading PBF files will not be able to read it.
+
+Also from Libosmium version 2.16 you can set the compression level with the
+file format option `pbf_compression_level`. Allowed values depend on the
+PBF compression used.
+
+| PBF compression | Option | Level     |
+| --------------- | ------ | --------- |
+| No compression  | `none` | n/a       |
+| ZLIB            | `zlib` | 0 - 9     |
+| LZ4             | `lz4`  | 1 - 65537 |
+
 PBF files contain a string table in each data block. Some programs sort this
 string table for slightly better compression. Osmium does not do this to make
 writing of PBF files faster.
 
 Usually PBF files contain all the metadata for objects such as changeset id,
-username, etc. To save some space you can disable writing of metatdata with the
+username, etc. To save some space you can disable writing of metadata with the
 format option `add_metadata=false`.
 

_file_formats_manual/10_format_comparison.md

@@ -16,10 +16,12 @@ But sometimes you can decide. Here are some guidelines:
   writing is fast in Osmium, because it uses multithreading. The only drawback
   is that you can't easily look inside those files because of the binary
   format.
-* You can disable compression (option `pbf_compression=none`) on PBF files
-  which makes them larger but faster to read. This might make sense if you
-  will read those files very often and aren't concerned about disk usage. You
-  have to experiment.
+* You can use LZ4 compression (option `pbf_compression=lz4`) on PBF files or
+  disable compression altogether (option `pbf_compression=none`) which makes
+  them larger but faster to read. This might make sense if you will read those
+  files very often and aren't concerned about disk usage. You have to
+  experiment. Note that most other PBF-reading programs will not support the
+  LZ4 compression.
 * The OSM API uses the XML format, so if you interact with that API, you'll
   want to use XML. Also OSM change files only come in XML format, so most
   software can only use them in that format.