Stuck in trying to add .ass subtitles to MP4 video

[cgkas]

Hello to all,

Maybe someone could help me.

I want to add ssa subtitles to video.

I've tried with VLC. If I play the video and add subtitles file VLC shows correctly the ssa subtitles but if I convert/save the same video adding the subtitles file, the output doesn't contain the subtitles.

Then I've tried with ffmpeg like this

ffmpeg -i video.mp4 -vf "ass=subtitle.ass" -strict -2 out.mp4

The output shows the subtitles, but the aspect is changed and the subtitles appear partially or sometimes cutted since the scale is changed and I would like to get the same aspect ratio (16:9) and same width x height as input video. Or even better reduce video size with same aspect ratio

How can I do that with ffmpeg, VLC or another open source tool?

I can share this log:

user@H:/mnt/d/VIDEOS$ ffmpeg -i input.mp4 -vf ass=subtitles.ass -v 40 -strict -2 out.mp4
ffmpeg version 2.8.14-0ubuntu0.16.04.1 Copyright (c) 2000-2018 the FFmpeg developers
  built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.9) 20160609
  configuration: --prefix=/usr --extra-version=0ubuntu0.16.04.1 --build-suffix=-ffmpeg --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --cc=cc --cxx=g++ --enable-gpl --enable-shared --disable-stripping --disable-decoder=libopenjpeg --disable-decoder=libschroedinger --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzvbi --enable-openal --enable-opengl --enable-x11grab --enable-libdc1394 --enable-libiec61883 --enable-libzmq --enable-frei0r --enable-libx264 --enable-libopencv
  libavutil      54. 31.100 / 54. 31.100
  libavcodec     56. 60.100 / 56. 60.100
  libavformat    56. 40.101 / 56. 40.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 40.101 /  5. 40.101
  libavresample   2.  1.  0 /  2.  1.  0
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.101 /  1.  2.101
  libpostproc    53.  3.100 / 53.  3.100
Routing option strict to both codec and muxer layer
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf56.40.101
  Duration: 00:04:06.06, start: 0.000000, bitrate: 450 kb/s
    Stream #0:0(und): Video: h264 (Main), 3 reference frames (avc1 / 0x31637661), yuv420p(tv, bt709), 854x480 (864x480) [SAR 1:1 DAR 427:240], 314 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
[Parsed_ass_0 @ 0x7f7880] Raster: FreeType 2.6.1
[Parsed_ass_0 @ 0x7f7880] Shaper: FriBidi 0.19.7 (SIMPLE) HarfBuzz-ng 1.0.1 (COMPLEX)
[Parsed_ass_0 @ 0x7f7880] Initialized
[Parsed_ass_0 @ 0x7f7880] Using font provider fontconfig
[Parsed_ass_0 @ 0x7f7880] File size: 3368
[Parsed_ass_0 @ 0x7f7880] [0x826cb0] Style: Default,Goudy Old Style,22,&H002DD8DB,&H000000FF,&H00000000,&H00000000,-1,0,0,0,100,100,0,0,1,2,2,2,10,10,10,1
[Parsed_ass_0 @ 0x7f7880] Added subtitle file: 'subtitles.ass' (2 styles, 27 events)
[graph 0 input from stream 0:0 @ 0x8ed880] w:854 h:480 pixfmt:yuv420p tb:1/30000 fr:30000/1001 sar:1/1 sws_param:flags=2[graph 1 input from stream 0:1 @ 0x8f2ee0] tb:1/44100 samplefmt:fltp samplerate:44100 chlayout:0x3
[libx264 @ 0x82bd00] using SAR=1/1
[libx264 @ 0x82bd00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
[libx264 @ 0x82bd00] profile High, level 3.1
[libx264 @ 0x82bd00] 264 - core 148 r2643 5c65704 - H.264/MPEG-4 AVC codec - Copyleft 2003-2015 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'out.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf56.40.101
    Stream #0:0(und): Video: h264 (libx264), -1 reference frame ([33][0][0][0] / 0x0021), yuv420p, 854x480 [SAR 1:1 DAR 427:240], q=-1--1, 29.97 fps, 30k tbn, 29.97 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      encoder         : Lavc56.60.100 libx264
    Stream #0:1(eng): Audio: aac ([64][0][0][0] / 0x0040), 44100 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
      encoder         : Lavc56.60.100 aac
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  Stream #0:1 -> #0:1 (aac (native) -> aac (native))
Press [q] to stop, [?] for help
[Parsed_ass_0 @ 0x7f7880] Neither PlayResX nor PlayResY defined. Assuming 384x288
[Parsed_ass_0 @ 0x7f7880] fontselect: (Goudy Old Style, 700, 0) -> /usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf, 0, DejaVuSans-Bold
No more output streams to write to, finishing.e=00:04:05.22 bitrate= 562.3kbits/s
frame= 7373 fps=142 q=-1.0 Lsize=   17301kB time=00:04:06.06 bitrate= 576.0kbits/s
video:13086kB audio:3963kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.480544%
Input file #0 (input.mp4):
  Input stream #0:0 (video): 7373 packets read (9668740 bytes); 7373 frames decoded;
  Input stream #0:1 (audio): 10597 packets read (3937072 bytes); 10597 frames decoded (10851328 samples);
  Total: 17970 packets (13605812 bytes) demuxed
Output file #0 (out.mp4):
  Output stream #0:0 (video): 7373 frames encoded; 7373 packets muxed (13399929 bytes);
  Output stream #0:1 (audio): 10597 frames encoded (10851328 samples); 10598 packets muxed (4058185 bytes);
  Total: 17971 packets (17458114 bytes) muxed
[libx264 @ 0x82bd00] frame I:38    Avg QP:16.75  size: 22811
[libx264 @ 0x82bd00] frame P:3026  Avg QP:22.01  size:  3818
[libx264 @ 0x82bd00] frame B:4309  Avg QP:24.78  size:   227
[libx264 @ 0x82bd00] consecutive B-frames: 20.0%  5.0%  3.4% 71.6%
[libx264 @ 0x82bd00] mb I  I16..4: 34.7% 50.6% 14.7%
[libx264 @ 0x82bd00] mb P  I16..4:  1.8%  3.4%  0.2%  P16..4: 24.0%  6.6%  5.1%  0.0%  0.0%    skip:59.0%
[libx264 @ 0x82bd00] mb B  I16..4:  0.1%  0.1%  0.0%  B16..8: 14.3%  0.1%  0.0%  direct: 0.3%  skip:85.0%  L0:39.0% L1:59.1% BI: 1.9%
[libx264 @ 0x82bd00] 8x8 transform intra:60.3% inter:53.1%
[libx264 @ 0x82bd00] coded y,uvDC,uvAC intra: 23.0% 35.3% 6.9% inter: 5.4% 5.7% 0.4%
[libx264 @ 0x82bd00] i16 v,h,dc,p: 47% 22% 13% 18%
[libx264 @ 0x82bd00] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 36% 16% 34%  2%  2%  2%  2%  2%  2%
[libx264 @ 0x82bd00] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 29% 20% 11%  5%  8%  7%  7%  6%  6%
[libx264 @ 0x82bd00] i8c dc,h,v,p: 61% 16% 20%  4%
[libx264 @ 0x82bd00] Weighted P-Frames: Y:17.8% UV:16.1%
[libx264 @ 0x82bd00] ref P L0: 70.2% 11.5% 13.4%  4.9%  0.0%
[libx264 @ 0x82bd00] ref B L0: 91.9%  7.0%  1.1%
[libx264 @ 0x82bd00] ref B L1: 96.6%  3.4%
[libx264 @ 0x82bd00] kb/s:435.73

Then I tried to in [Script Info] section within subtitle.ass below lines but it didn't help.

PlayResX: 854
PlayResY: 480

Thanks in advance

[sneaker]

Strange. All is SAR 1:1 so I wouldn't expect any difficulties. Try:

PlayResX: 720
PlayResY: 480

if it doesn't work try:

PlayResX: 1920
PlayResY: 1080

and finally:

PlayResX: 1280
PlayResY: 720

[cgkas]

Strange. All is SAR 1:1 so I wouldn't expect any difficulties. Try:

PlayResX: 720
PlayResY: 480

if it doesn't work try:

PlayResX: 1920
PlayResY: 1080

and finally:

PlayResX: 1280
PlayResY: 720

Hello sneaker,

Trying the 3 ways you suggested I got the following error:

I got this error

[Parsed_ass_0 @ 0x16ad880] Shaper: FriBidi 0.19.7 (SIMPLE) HarfBuzz-ng 1.0.1 (COMPLEX)
[Parsed_ass_0 @ 0x16ad880] Using font provider fontconfig
[Parsed_ass_0 @ 0x16ad880] ass_read_file(subtitle.ass): fopen failed
[Parsed_ass_0 @ 0x16ad880] Could not create a libass track when reading file 'subtitle.ass'
[AVFilterGraph @ 0x16ae920] Error initializing filter 'ass' with args 'subtitle.ass'
Error opening filters!

[sneaker]

Seems like ffmpeg can't read the .ass file at all anymore. Check again that you are in the correct working folder, you didn't accidentically deleted the script etc.

[cgkas]

It was a typo in subtitle file. Now I was able to try the 3 resolutions you suggested.

For the first 720x480 the text appears I think with correct size, but with wrong position.

For the other 2 resolutions the text size looks very small and the same for the position, is wrong.

I don´t know if some previous step is needed like demux the subtitles in a mp4 stream and then mix with the input. I don´t have more ideas.

I.ve tried with XMecia Recode too and I´m not sure if I´m doing something wrong but the subtitles don´t appear in output.

Thanks for help so far

[sneaker]

Basically, PlayResX and PlayResY control the scaling. I don't know how you think it should look. Just play a bit with the values until you like the result. There is no magic behind it.

Is the font ffmpeg loads identical to the one VLC is using?

[cgkas]

Basically, PlayResX and PlayResY control the scaling. I don't know how you think it should look. Just play a bit with the values until you like the result. There is no magic behind it.

Is the font ffmpeg loads identical to the one VLC is using?

No, the font type and size is different from that showed on VLC.

I don't know how VLC presents correctly the subtitles without adding resolution settings to subtitles file. Some missing parameter in ffmpeg command maybe?