FFmpeg drawtext over multiple lines

Question

I have the code:

import subprocess , os

ffmpeg = "C:\\ffmpeg_10_6_11.exe"
inVid = "C:\\test_in.avi"
outVid = "C:\\test_out.avi"

if os.path.exists( outVid ):
os.remove( outVid )
proc = subprocess.Popen(ffmpeg + " -i " + inVid + ''' -vf drawtext=fontfile=/Windows/Fonts/arial.ttf:text="onLine1 onLine2 onLine3":fontcolor=white:fontsize=20 -y ''' + outVid , shell=True, stderr=subprocess.PIPE)
proc.wait()
print proc.stderr.read()
os.startfile( outVid )

to write text to a video file. But I want to write out many lines of text instead of just having it all on the one line.

Pls help. Thanks

Answer 1

This answer is probably a bit late for you, but you can specify multiple drawtexts on one file by using the [in] tag and listing each drawtext using commas. This allows you to use multiple lines if you orient each drawtext through their respective positioning methods. In your example, the command line would look something like this (puts the first line in the middle of the screen, and puts each subsequent line 25 pixels down):

ffmpeg -i test_in.avi -vf "[in]drawtext=fontsize=20:fontcolor=White:fontfile='/Windows/Fonts/arial.ttf':text='onLine1':x=(w)/2:y=(h)/2, drawtext=fontsize=20:fontcolor=White:fontfile='/Windows/Fonts/arial.ttf':text='onLine2':x=(w)/2:y=((h)/2)+25, drawtext=fontsize=20:fontcolor=White:fontfile='/Windows/Fonts/arial.ttf':text='onLine3':x=(w)/2:y=((h)/2)+50[out]" -y test_out.avi

Answer 2

Looking at the source code in ffmpeg (vs_drawtext.c):

static inline int is_newline(uint32_t c)
{
    return c == '\n' || c == '\r' || c == '\f' || c == '\v';
}

so you can try inserting \f or \v in your text line which correspond to ^L or ^K characters. For example:

-filter_complex "[in] drawtext=fontsize=40:fontcolor=white:fontfile=/usr/share/fonts/truetype/ttf-dejavu/DejaVuSans.ttf:x=(w-tw)/2:y=(h-th)/2:box=1:[email protected]:text='two^Llines'[out]"

^L being the actual Ctrl-L character and not ^ and L obviously.