Re: Video generation, bash script, keeps sync in spite of tempo changes

[Knut Petersen]

Am 13.09.2016 um 02:29 schrieb Paul:
> Hi Knut,
>
> Sounds cool!  I'd like to check it out when I get a chance.  I'm curious how it 
> compares with ly2video?
>
> https://github.com/aspiers/ly2video 

Some differences between my script and ly2video.py:
=================================
-> ly2video supports older versions of lilypond, my script needs at least 
version 2.19.23
->  ly2video requires clean 7-bit source files, it's almost unusable for vocal 
music if the lyrics text
      requires characters from european languages that use diacritics (german, 
french, ...) or completely
      different characters (russian ....). My script does not have this 
limitation.
-> ly2video is very slow compared to my script (see below), especially on a 
multi-core cpu
-> ly2video files are big, even if you turn off the cursor
-> ly2video uses a single very long system and cuts part from that. This is a 
problem if the
     number of instruments used is not constant.
-> my script does not generate a cursor as I believe that it is useless --- if 
you know how to read
     music, you do not need it, if you don't know how to read music it does not 
help either.
-> There are some bugs in ly2video that cause it to loose sync sometimes (but 
there are probably
     bugs in my script / videohelper.ily too)

Some measurements
=============

Test: Converting a lilypond source of J.S. Bach Invention Nr. 1
System: OS: Linux, cpu: i4790K cpu

ly2video, set to generate no cursor and identical Y-resolution
======================================
Processing time: 63.0 +/- 0.5 seconds
size of video file: 10.498.048 bytes

My script with h264 preset "ultrafast"
=======================
Processing time: 6.45 +/- 0.15 seconds (includes lilypond processing time of 
1.0 +/- 0.05s)
size of video file: 4.134.850 bytes

My script with h264 preset "veryslow"
=======================
Processing time 12.5 +/- 0.1 seconds (includes lilypond processing time of 1.0 
+/- 0.05s)
size of video file: 1.843.136 bytes

Attached find a new version of my script and an example source
========================================
Changes: -> Add metronome ticks at start of music
                -> remove temporary files
                -> limit number of parallel jobs to (virtual or real) cpu cores 
+ 1
                -> fix a bug in videohelper.ily
Missing :  -> errors are ignored most of the time ...

cu,
 Knut

mkvideo
Description: Text document

videohelper.ily
Description: Text document

JSBI1.ly
Description: Text Data