[FFmpeg-user] Burned dialog not appearing on large videos if time interval reduced

Aameer Rafiq Wani aameer.rafiq at gmail.com
Wed Mar 23 14:14:11 CET 2016

Hey Guys,
This is in continuation of my previous question, since I didn't get any
response from you guys so I tried to look deeper into the issue and tried
with different video lengths and different videos and I got the expected
results for all except this video https://vimeo.com/140349795
I was using as a test video for long video tests, still not sure why cant
we see the second dialog(subtitle) when we reduce the time interval below 1
sec. Would appreciate if someone has some pointers to share which could
explain this unusual behavior.Thanks

On Mon, Mar 21, 2016 at 11:34 AM, Aameer Rafiq Wani <aameer.rafiq at gmail.com>

> hey guys,
> I am facing an issue while I try to burn a dialog on a large video when I
> try to reduce the time interval for which it should appear it seizes to
> show up if the time interval is less than 1 sec while this is not the case
> with smaller videos and we can go down to approx 0.15 seconds with videos
> of 44 secs or 40 mins.
> I am sharing my encoding code snippet from my shell script ,which is like:
> #360 version
> (time ffmpeg -i test.mp4 -profile:v baseline -level 4.0 -vf
> "scale=-2:360,subtitles='subtitle_test.ass':force_style='FontName=Aaargh/Aaargh.ttf,PrimaryColour=&H664c4c4c"
>  -start_number 0 -hls_time 10 -hls_list_size 0 -f hls
> /mnt/s3_temp/bucketname/project_id/videos/3342/3428_360_.m3u8" && echo "360
> version:" >> encoding_logs.log ) 2>> encoding_logs.log &
> and the subtitle_test.ass file is like (e.g for 119m 31 s videos which is
> 3.9 GB)
> [Script Info]
> ; Script generated by FFmpeg/Lavc57.24.103
> ScriptType: v4.00+
> PlayResX: 384
> PlayResY: 288
> [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,16,&H99999999,&H99999999,&H0,&H0,0,0,0,0,100,100,0,0,1,0,0,2,10,10,10,0
> Style:
> Hidden,Arial,16,&H99999999,&H99999999,&H0,&H0,0,0,0,0,100,100,0,0,1,0,0,6,10,10,10,0
> [Events]
> Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect,
> Text
> Dialogue: 0,0:00:00.00,1:59:31.783,Default,,0,0,0,,dialog1
> Dialogue: 0,0:39:50.927,0:39:51.927,Hidden,,0,0,10,,dialog2
> Note the timings for dailog2 which is
> dialog2 start : 0:39:50.927
> dialog2 end : 0:39:51.927
> dialog2_time_interval = (dialog2 start time- dialog2 end time) = 1 sec
> what I am trying to achieve is to display the first dialog for the entire
> length and the second dialog for smallest amount of time possible.For now
> what I have achieved is for smaller videos of few seconds or few mins the
> dialog2 appears even when the dialog2_time_interval is less than 1 sec. I
> got a successful test with dialog2_time_interval=0.15 sec(approximately 150
> milliseconds).
> But with large videos say in above case the dialog2 appears only when the
> dialog2_time_interval is greater than or equal to 1 sec. I want to know is
> there a relation between the video length and dialog2_time_interval which i
> should keep in mind to minimize dialog2_time_interval for video of any
> length.
> Moreover I also see a delay of few seconds with the dialog , i.e they
> appear few milliseconds or secs after they were supposed to appear, is that
> normal.Thanks.
> For some reason if the details mentioned here are not enough I have a
> small blog post relating the same which could through a little more light
> on this subject here(http://aameer.github.io/cloud-computing-101/). Thanks
> Regards,
> email: aameer.rafiq at gmail.com
> websites: aameer.github.io <aameer at github.io>
> LinkedIn: http://in.linkedin.com/in/aameerwani

email: aameer.rafiq at gmail.com
websites: aameer.github.io <aameer at github.io> / aameer.weebly.com
Facebook: https://www.facebook.com/aameerrafiq.wani
LinkedIn: http://in.linkedin.com/in/aameerwani
Contact number: +919500083139
Current location: Bangalore  India.

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