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We are stoked to announce the release of liquidsoap 2.3.0
! 🎉 ✨
This release brings a lot of exciting changes. As usual, we recommend to first test it in a staging environment before deploying it to production. Migration notes for this release can be found here.
A lot of hard engineering work went into this release! The largest changes should that happened during this cycle were under the hood:
Complete re-implementation of the streaming cycle and clocks
This change allowed us to prepare the codebase to use OCaml's new multicore support in future releases and get rid of design decisions that were 20 years old now. Back then, we had no idea how things would evolve! In particular, we had to account for new form of content such as raw video and encoded content.
Instead of filling a partial frame during the streaming cycle, we are now manipulating chunks of immutable content, concatenating them to build a frame on each streaming cycle. This is much more inline with the logic underlying video and encoded content where pieces of content can happen at random time, according to their presentation timestamp (PTS) or decoder timestamp (DTS).
Abstracting content this way has allowed us to finally get rid of frame breaks doubling as both track marks and partial filling marks. With the new content model, track marks and metadata are first-class content and part of the frame generation.
If you have ever encountered any of the infamous #get_frame didn't add exactly one break!
fatal error, you know what we mean. This early design decision had plagued us for a while and it's wonderful to see it gone!
Along with these changes, we also reimplemented from scratch our notion of clocks, the abstract API that runs the main streaming cycles.
While clocks are still a pretty complex topic (self-sync, active vs. passive etc), we hope that this rewrite will clarify things. It was a good opportunity to clean up our implementation and use the experience gained about it in the recent years.
With these changes, clocks are now surfaced to the user via a clock
method on each source. This makes it possible to directly access source clocks, animate them in your script, etc. We've also started to support synchronous streaming scripts, which should make it possible to use liquidsoap as a CLI for offline processing.
Script caching and memory optimization
Another important new feature with this release is the ability to cache the standard library and user scripts. This allows liquidsoap to run much faster. More details are available in this blog post
Incidentally, script caching also has very important benefits for memory usage. This is documented here.
This feature is probably the most important one of this release for most users!
Internal autocue
Autocue, the method for computing the perfect crossfade has also been polished in this release. We have now switched to our internal implementation, which is available when enabling our ffmpeg
support.
You should be able to enable it by adding this to your script:
enable_autocue_metadata()
With this, all requests should resolve with the appropriate metadata so that any crossfade
produces perfect transitions!
Remember that this feature requires CPU-heavy computations on each track!
A lot of testing went into this feature so we are really thankful to our users for the support and patience!
Other new features
Here's a list of other notable changes in this release:
- Frame duration was dropped to
0.02s
. This should enhance streams latency and was made possible thanks to the new streaming implementation. See #4033 for a discussion about the trade-offs involved with this setting. - New support for video size-independent placement of video elements. This makes it possible to design video streams with different elements whose placement is independent of the final video resolution. See this blog post for an example of it.
- Support for NDI output. We always try to extend the scope of applications that can be interfaced with liquidsoap. In the future, we would like to add support for NDI inputs and extend the supported formats.
The rest of the changelog is included below.
As with each release, we want to thank all our users for their patience, early testing and collaboration to make this release possible. It's a testament to their help that we are able to ship this release with such a level of confidence despite all the major changes that happened in the code base.
Special thanks go to: @vitoyucepi, @gAlleb, @RM-FM, @Moonbase59, @Russsgithub, @gilou, Xogium, the whole AzuraCast and Radio France team and everyone who helped reporting, fixing and confirming bugs.
Thanks y'all!
2.3.0 (2024-11-27)
New:
- Rewrote the streaming API to work with immutable frame content. This
should greatly impact impredictable side-effect of the previous models w.r.t.
track marks, content sharing and more. This also impacts multiple operators
behavior. Mostly, things should be roughly the same with differences around
behaviors related to track marks (source.on_track
and etc). (#3577) - Added script caching layer for faster script startup time. See: https://www.liquidsoap.info/blog/2024-06-13-a-faster-liquidsoap/ for details (#3924, #3949, #3959 and #3977)
- Rewrote the clock/streaming loop layer. This prepares our streaming system to
support multicore when the OCaml compiler is mature enough to allow it. Clocks
are now attached to sources via theirclock
methods. Returned value is a stripped
downclock
variable. Users can use theclock
function to retrieve the full
methods, e.g.s = sine(); c = clock(s.clock)
. This value has advanced functions
for clock control such asstart
/stop
,ticks
andself_sync
to check for
self-sync
. (#3781) - Allow frames duration shorter than one video frames, typically values under
0.04s
.
Smaller frames means less latency and memory consumption at the expense of
a higher CPU usage (#3607) - Change default frame duration to
0.02s
(#4033) - Optimized runtime (#3927, #3928, #3919)
- Added NDI output support (#4181)
- Added
finally
to execute code regardless of whether or not an exception is raised
(see: #3895 for more details). - Added support for Spinitron submission API (#4158)
- Removed gstreamer support. Gstreamer's architecture was never a good fit for us
and created a huge maintenance and debugging burden and it had been marked as
deprecated for a while. Most, if not all of its features should be available using
ffmpeg
. (#4036) - Removed
taglib
support. It is superseded by the internalocaml-metadata
module
and taglib, with its dependency on the C++ runtime library, has been causing issues
with binary builds portability and crashes with the (not yet supported) OCaml 5
compiler. (#4087) - Added
video.canvas
to make it possible to position video elements independently
of the rendered video size (#3656, blog post) - Added cover manager from an original code by @vitoyucepi (#3651)
- Added non-interleaved API to
%ffmpeg
encoder, enabled by default when only
one stream is encoded. - Allow trailing commas in record definition (#3300).
- Added
metadata.getter.source.float
(#3356). - BREAKING: Added
duration
andticks
to metadata available when computing HLS segment names (#4135) - Added optional
main_playlist_writer
tooutput.file.hls
and
derivated operator (#3484) - Added
is_nan
,is_infinite
,ceil
,floor
,sign
andround
(#3407) - Added
%track.drop
to the%ffmpeg
encoder to allow partial encoding
of a source's available tracks (#3480) - Added
let { foo? } = ...
pattern matching (#3481) - Added
metadata.replaygain
method to extract unified replay gain value from metadata (#3438). - Added
metadata.parse.amplify
to manually parse amplify override metadata. - Added
compute
parameter tofile.replaygain
to control gain calculation (#3438). - Added
compute
parameter toenable_replaygain_metadata
to control replay gain calculation (#3438). - Added
copy:
protocol (#3506) - Added
file.touch
. - Added support for sqlite databases (#3575).
- Added
string.of_int
andstring.spaces
. - Added
list.assoc.nullable
. - Added
source.cue
(#3620). - Added
string.chars
(#4111) - Added atomic file write operations.
- Added new
macos_say
speech synthesis protocol. Make it the default implementation for thesay:
protocol onmacos
. - Added
settings.request.timeout
to set the request timeout globally.
Changed:
- Reimplemented
request.once
,single
and more usingsource.dynamic
. Removed experiment
flag onsource.dynamic
. The operator is considered stable enough to define advanced sources
but the user should be careful when using it. - Mute SDL startup messages (#2913).
int
can optionally raises an error when passingnan
orinfinity
,int(infinity)
now returnsmax_int
andint(-infinity)
returnsmin_int
. (#3407)- Made default font a setting (#3507)
- Changed internal metadata format to be immutable (#3297).
- Removed
source.dump
andsource.drop
in favor of saferrequest.dump
andrequest.drop
.
source.{dump, drop}
can still be implemented manually when needed and with the proper
knowledge of what's going on. - Allow a getter for the offset of
on_offset
and dropped the metadata
mechanism for updating it (#3355). string.length
andstring.sub
now default toutf8
encoding (#4109)- Disable output paging when
TERM
environment variable is not set. - Allow running as
root
user insidedocker
container by default (#3406). - Run
check_next
before playlist's requests resolutions (#3625) - Set
force
totrue
by default infile.copy
to make operator behave
as expected. - BREAKING: Float comparison now follows the expected specs, in particular:
nan == x
is alwaysfalse
and
nan != x
is alwaystrue
. Usefloat.is_nan
to test if a float isnan
. - BREAKING:
replaygain
no longer takesebu_r128
parameter (#3438). - BREAKING: assume
replaygain_track_gain
always stores volume in dB (#3438). - BREAKING: protocols can now check for nested static uri. Typically, this means
that requests for an uri of the form:annotate:key="value",...:/path/to/file.mp3
is now considered infallible if/path/to/file.mp3
can be decoded. - Added
parents
option offile.mkdir
(#3600, #3601). - Added
forced_major_collections
record field to the result ofruntime.gc.stat()
and
runtime.gc.quick_stat()
(#3783). - Changed the port for the built-in Prometheus exporter to
9599
(#3801). - Set
segments_overheader
in HLS outputs to disable segments cleanup altogether. - Added support for caching LV2 and LADSPA plugins (#3959).
- Pulseaudio input and output now restart on pulseaudio errors (#4174).
Fixed: