[FFmpeg-user] FFmpeg DASH Optional Adaptation Set

[Dennis Mungai]

On Thu, 15 Jul 2021 at 16:52, Mar Andrés López <mar.andres.l at gmv.com> wrote:

> Dear All,
>
>
> I am using the following FFmpeg command for dash generation,
>
>
> ffmpeg -i video.mpeg -preset superfast -r 30 -vcodec libx264 -acodec aac
> -b:a 128k -ac 1 -ar 44100 -map v:0 -b:v:0 1500000 -s:v:0 768x432 -map v:0
> -b:v:1 750000 -s:v:1 640x360 -map v:0 -b:v:2 500000 -s:v:2 512x288 -map
> 0:a? -f dash -adaptation_sets "id=0,streams=v id=1,streams=a"
> -utc_timing_url manifest-mpd.
>
>
> Currently the manifest is creating an empty adaptation set for videos
> which do not contain audio:
>
>
> <AdaptationSet id="1" contentType="audio" startWithSAP="1"
> segmentAlignment="true" bitstreamSwitching="true"></AdaptationSet>
>
>
> I thougth that by using -map 0:a? i would make it optional but it is not
> the case. As you see above the adaptation set is still created.
>
>
>
What version of FFmpeg are you using?

>
>