Recherche avancée

Sur d’autres sites (11982)

• Text in ass subtitles is displayed smaller then should

  3 septembre 2024, par Armen Sanoyan

  I add subtitles to video by ffmpeg using two different ways. The first way is by using drawtext command and this way everything works perfectly. Here is the command

  


  ffmpeg -i ./input.mp4 -vf "drawtext=text='reise':fontfile=../fonts/Audiowide-Regular.ttf:fontsize=55:fontcolor=white:x=0:y=683" -codec:a copy ./output.mp4


  


  The second way is by using ass subtitles file. This way I got smaller letters and wrong y position for text. Below is the ass subtitle file content

  


  
[Script Info]
Title: Advanced Highlighted Subtitle Example
ScriptType: v4.00+
WrapStyle: 0
PlayResX: 1048
PlayResY: 750

[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,Audiowide Regular,55,&HFFFFFF,&H00FFFFFF,&H00000000,&H00000000,1,0,0,0,100,100,0,0,0,0,0,2,10,10,10,1

[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text

Dialogue: 0,00:00:0.00,00:00:2.38,Default,,0,0,0,,{\pos(0,683)\an4}reise


  


  And command for second approach

  


  ffmpeg -i ./input.mp4 -vf "ass=../subtitles.ass:fontsdir=../fonts/Audiowide-Regular.ttf"  ../output.mp4


  


  So they both get the same video, same font and same text. The problem is that in case of using ass file the text is much smaller and dislocated

  


  The numbers on axis indicate sizes by pixels.
As you can see in second image it's much smaller and has wrong y coordinate. It seems like it has wrong scaling numbers. What is wrong with my ass file configs ?

  


  I have tried solution from [universalmediaserver]to remove PlayResX/Y, but it doesn't work. (https://www.universalmediaserver.com/forum/viewtopic.php?t=5907). I also tried to measure the text width in many other ways(like in html rendered in browser, canvas...), so I'm pretty sure that drawtext does give correctly rendered width. The problem is related to ass subtitles file. Also if I use popular fonts like Arial the deviation is much less.

  


• got invalid text position and size for ass subtitles

  1er septembre 2024, par Armen Sanoyan

  I add subtitles to video by ffmpeg using two different ways. The first way is by using drawtext command and this way everything works perfectly. Here is the command

  


  ffmpeg -i ./input.mp4 -vf "drawtext=text='reise':fontfile=../fonts/Audiowide-Regular.ttf:fontsize=55:fontcolor=white:x=0:y=683" -codec:a copy ./output.mp4


  


  The second way is by using ass subtitles file. This way I got smaller letters and wrong y position for text. Below is the ass subtitle file content

  


  
[Script Info]
Title: Advanced Highlighted Subtitle Example
ScriptType: v4.00+
WrapStyle: 0
PlayResX: 1048
PlayResY: 750

[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,Audiowide Regular,55,&HFFFFFF,&H00FFFFFF,&H00000000,&H00000000,1,0,0,0,100,100,0,0,0,0,0,2,10,10,10,1

[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text

Dialogue: 0,00:00:0.00,00:00:2.38,Default,,0,0,0,,{\pos(0,683)\an4}reise


  


  And command for second approach

  


  ffmpeg -i ./input.mp4 -vf "ass=../subtitles.ass:fontsdir=../fonts/Audiowide-Regular.ttf"  ../output.mp4


  


  So they both get the same video, same font and same text. The problem is that in case of using ass file the text is much smaller and dislocated

  


  The numbers on axis indicate sizes by pixels.
As you can see in second image it's much smaller and has wrong y coordinate. It seems like it has wrong scaling numbers. What is wrong with my ass file configs ?

  


  I have tried solution from [universalmediaserver]to remove PlayResX/Y, but it doesn't work. (https://www.universalmediaserver.com/forum/viewtopic.php?t=5907). I also tried to measure the text width in many other ways(like in html rendered in browser, canvas...), so I'm pretty sure that drawtext does give correctly rendered width. The problem is related to ass subtitles file. Also if I use popular fonts like Arial the deviation is much less.

  


• FFmpeg audio formats : ipod vs mov (for ALAC)

  22 juillet 2022, par Fabien Snauwaert

  In converting to Apple Lossless (ALAC) using FFmpeg, I have two options :

  


  ffmpeg -y -i whatever.wav -b:a 256k -ar 16000 -ac 1 -f ipod -acodec:a alac whatever.ipod.m4a
# Output #0, ipod, to 'content/tests/comparing-codecs/whatever.ipod.m4a':

ffmpeg -y -i whatever.wav -b:a 256k -ar 16000 -ac 1 -f mov -acodec:a alac whatever.mov.m4a
# Output #0, mov, to 'content/tests/comparing-codecs/whatever.mov.m4a':


  


  (I could also leave the -f alone, which the defaults to ipod.)

  


  This results in near identical files, from ffprobe :

  


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'content/tests/comparing-codecs/whatever.ipod.m4a':
  Metadata:
    major_brand     : M4A
    minor_version   : 512
    compatible_brands: isomiso2
    encoder         : Lavf58.29.100
  Duration: 00:00:01.46, start: 0.000000, bitrate: 67 kb/s
    Stream #0:0(und): Audio: alac (alac / 0x63616C61), 16000 Hz, mono, s16p, 63 kb/s (default)
    Metadata:
      handler_name    : SoundHandler


  


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'content/tests/comparing-codecs/whatever.mov.m4a':
  Metadata:
    major_brand     : qt
    minor_version   : 512
    compatible_brands: qt
    encoder         : Lavf58.29.100
  Duration: 00:00:01.46, start: 0.000000, bitrate: 67 kb/s
    Stream #0:0: Audio: alac (alac / 0x63616C61), 16000 Hz, mono, s16p, 63 kb/s (default)
    Metadata:
      handler_name    : SoundHandler


  


  Only the file size is slightly different, with the ipod file 43 bytes smaller.

  


  I'm able to play both files in on macOS and iPhone, at least on the devices I had access to.

  


  My question is : is there any practical difference between formats ? Is a given format preferable for a specific use ?