Vertical scrolling of subtitles

[jollye]

I've got a question that may be related to VSFilter or the ASS format. Please let me know if this is the case.

So my problem is the following. I want to generate some subtitles that will scroll the video vertically and I want to control their speed in pixels/frame. I tried using the Scroll up effect from the ASS format and it worked except that the speed of the subtitle is controlled by a magic number that is not explained in the documentation I've found (I need pixels/frame). So if somebody in this forum could propose another solution, I would be interested.

I post my scripts below:

My AVS script

clip=BlankClip(length=1000,width=1368,height=768,fps=50,pixel_type="RGB32",color=$000000)
clip=TextSub(clip,"vertical.ass")
return clip


vertical.ass

[Script Info]
; Script generated by Aegisub v2.1.0 RELEASE PREVIEW (SVN r1847, amz)
; http://www.aegisub.net
Title: Default Aegisub file
ScriptType: v4.00+
WrapStyle: 0
PlayResX: 1368
PlayResY: 768
ScaledBorderAndShadow: yes
Video Aspect Ratio: 0
Video Zoom: 4
Video Position: 143
Video File: vertical texts2.avs

[V4+ Styles]
Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding
Style: Default,Arial,32,&H00FFFFFF,&H000000FF,&H00000000,&H00000000,0,0,0,0,100,100,0,0,1,3.2,3.2,2,21,21,16,0

[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:20.00,Default,,0000,0000,0000,Scroll up;0;768;4;,{\pos(174,730)}ABCDEFGHIJKLM\NNOOORSTUVWXY\NZabcdefijklmnOOO\NrstuvwxyzABCDEF\N
Dialogue: 0,0:00:00.00,0:00:20.00,Default,,0000,0000,0000,Scroll up;0;768;3;,{\pos(650,768)}ABCDEFGHIJKLM\NNOOORSTUVWXY\NZabcdefijklmnOOO\NrstuvwxyzABCDEF\N
Dialogue: 0,0:00:00.00,0:00:20.00,Default,,0000,0000,0000,Scroll up;0;768;2;,{\pos(1200,769)}ABCDEFGHIJKLM\NNOOORSTUVWXY\NZabcdefijklmnOOO\NrstuvwxyzABCDEF\N

Thanks for your help

[J_Darnley]

Since ASS does not use frames it will be very hard to give it a pixels/frame speed, it only uses time. Did you find the "ass-specs.doc" document? It says the speed is controlled by the delay value.
"Scroll up;y1;y2;delay[;fadeawayheight]"
...
The delay value can be a number from 1 to 100, and it slows down the speed of the scrolling - zero means no delay and the scrolling will be as fast as possible.
Alternatively you could use the the /move function in which you can set the start and finish positions and the start and end times.
\move(<x1>, <y1>, <x2>, <y2>[, <t1>, <t2>])
<x1>, <y1> The coordinate to start at.
<x2>, <y2> The coordinate to end at.
<t1>, <t2> Animation beginning, ending time offset [ms] (optional)
The origin of the movement is defined by the alignment type.