Adding subtitles to video fails with ffmpeg

Question

I am trying to add a subtitle to a video using ffmpeg and a .srt file. Using the command:

ffmpeg -i videopath.mp4 -i subtitlefilepath.srt -c:v libx264 -preset ultrafast -ar 44100 -ac 2 -ab 128k -strict -2 videooutput.mp4

.srt file looks like

1
00:00:00,30-->00:00:05,30
Sample sub title for video 

What is that 30 after duration?

Output:

ffmpeg version git-2013-12-11-3b28564 Copyright (c) 2000-2014 the FFmpeg developers  built on Jan 22 2014 13:22:00 with gcc 4.6 (GCC) 20120106 (peelease)  configuration: --arch=arm --target-os=linux --enable-cross-compile --cross-prefix=/Users/sunitha/Downloads/android-ndk-r9c/toolchains/arm-linux-androideabi-4.6/prebuilt/darwin-x86/bin/arm-linux-androideabi- --prefix=../build --sysroot=/Users/sunitha/Downloads/android-ndk-r9c/platforms/android-9/arch-arm --extra-cflags=' -I/Users/sunitha/Downloads/android-ndk-r9c/platforms/android-9/arch-arm/usr/include -I../libmp3lame/include -I../libx264/include -DANDROID -marm -march=armv6 ' --extra-ldflags=' -L/Users/sunitha/Downloads/android-ndk-r9c/platforms/android-9/arch-arm/usr/lib -L../libmp3lame/lib -L../libx264/lib' --disable-debug --enable-libmp3lame --enable-libx264 --disable-ffplay --disable-ffprobe --disable-ffserver --enable-avfilter --enable-decoders --enable-demuxers --enable-encoders --enable-filters --enable-indevs --enable-network --enable-parsers --enable-protocols --enable-swscale --enable-gpl --enable-nonfree
libavutil      52. 63.100 / 52. 63.100  
libavcodec     55. 48.102 / 55. 48.102  
libavformat    55. 25.101 / 55. 25.101  
libavdevice    55.  5.102 / 55.  5.102  
libavfilter     4.  1.100 /  4.  1.100  
libswscale      2.  5.101 /  2.  5.101  
libswresample   0. 17.104 /  0. 17.104  
libpostproc    52.  3.100 / 52.  3.100

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/storage/emulated/0/DCIM/Camera/20141022_125926.mp4':  
    Metadata:    
        major_brand     : isom    
        minor_version   : 0    
        compatible_brands: isom3gp4    
        creation_time   : 2014-10-22 07:29:39  
        Duration: 00:00:08.58, start: 0.000000, bitrate: 11752 kb/s  
    Stream #0:0(eng): Video: h264 (Baseline) (avc1 / 0x31637661), yuv420p(tv, smpte170m), 1280x720, 11758 kb/s, 29.33 fps, 30 tbr, 90k tbn, 180k tbc (default)    
    Metadata:      
        rotate          : 90      
        creation_time   : 2014-10-22 07:29:39      
        handler_name    : VideoHandle    
    Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 48000 Hz, mono, fltp, 60 kb/s (default)    
    Metadata:      
        creation_time   : 2014-10-22 07:29:39      
        handler_name    : SoundHandle

Input #1, srt, from '/storage/emulated/0/DCIM/Camera/subtitle.srt':  Duration: N/A, bitrate: N/A    
Stream #1:0: Subtitle: subrip

[libx264 @ 0x11cf050] using cpu capabilities: ARMv6 NEON[libx264 @ 0x11cf050] profile Constrained Baseline, level 3.1
[libx264 @ 0x11cf050] 264 - core 140 r2377 1ca7bb9 - H.264/MPEG-4 AVC codec - Copyleft 2003-2013 - http://www.videolan.org/x264.html - options: cabac=0 ref=1 deblock=0:0:0 analyse=0:0 me=dia subme=0 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=1 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=0 keyint=250 keyint_min=25 scenecut=0 intra_refresh=0 rc=crf mbtree=0 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=0

Output #0, mp4, to '/storage/emulated/0/VideoOverLay/videooverlay1413965066659.mp4':  
    Metadata:    
        major_brand     : isom    
        minor_version   : 0    
        compatible_brands: isom3gp4    
        encoder         : Lavf55.25.101    
    Stream #0:0(eng): Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 1280x720, q=-1--1, 15360 tbn, 30 tbc (default)    
    Metadata:      
        rotate          : 90      
        creation_time   : 2014-10-22 07:29:39      
        handler_name    : VideoHandle    
    Stream #0:1(eng): Audio: aac ([64][0][0][0] / 0x0040), 44100 Hz, stereo, fltp, 128 kb/s (default)    
    Metadata:      
        creation_time   : 2014-10-22 07:29:39      
        handler_name    : SoundHandle

Stream mapping:  
    Stream #0:0 -> #0:0 (h264 -> libx264)  
    Stream #0:1 -> #0:1 (aac -> aac)

Press [q] to stop, [?] for help
frame=    0 fps=0.0 q=0.0 size=       0kB time=00:00:00.47 bitrate=   0.8kbits/s    
frame=    0 fps=0.0 q=0.0 size=       0kB time=00:00:00.91 bitrate=   0.4kbits/s    
frame=    3 fps=1.2 q=23.0 size=      38kB time=00:00:01.00 bitrate= 311.9kbits/s    
frame=    6 fps=1.9 q=22.0 size=      7
10-22 13:35:08.365: D/dalvikvm(1754): GC_CONCURRENT freed 1968K, 26% free 16486K/22120K, paused 14ms+6ms, total 59ms
10-22 13:35:08.365: I/exit code >>>>>>>>..(1754): 0
10-22 13:35:08.365: I/exit code >>>>>>>>..(1754): 0

I can't see any subtitles on the video. Where's the problem?

Answer 1

You're not telling ffmpeg to use the subtitles. With multiple inputs ffmpeg will only map one, IIRC:

Stream mapping:  
    Stream #0:0 -> #0:0 (h264 -> libx264)  
    Stream #0:1 -> #0:1 (aac -> aac)

So try something like:

ffmpeg -i videopath.mp4 -i subtitlefilepath.srt \
-c:v libx264 -preset ultrafast \
-ar 44100 -ac 2 -ab 128k -strict -2 \
-c:s mov_text -map 0 -map 1 \
videooutput.mp4

This would copy the subtitles as-is and map the input video (-map 0) and subtitle file (-map 1) to the output. You should see something like this:

Stream mapping:  
    Stream #0:0 -> #0:0 (h264 -> libx264)  
    Stream #0:1 -> #0:1 (aac -> aac)
    Stream #1:0 -> #1:0 (srt -> mov_text)

You could also use the subtitles filter to hardcode subs. For that you need to compile ffmpeg version with libass though, which is not the case for the one you're using.