[FFmpeg-user] How to transcode to HLS and DASH with mp4 and webm all at once

[Stefan Oltmanns]

Hi Alvaro,

> you should be able to generate the mpd file for DASH

Yes, but how? ffmpeg proved an easy way to generate webm-dash-manifests,
but I cannot figure out how to use it to include the MPEG segments.

And MPEG-DASH manifest creation afterwards I couldn't figure out at all,
only with at least remuxing the files.

Best regards
Stefan


Am 12.10.22 um 10:47 schrieb Alvaro Jimenez:
> DASH is codec agnostic, so if you already have or generate the ts segments for HLS, you should be able to generate the mpd file for DASH to play back the same segments you would use for HLS. I have used the m4s segments, and I have seen a common instance of lip sync issues that I have never see using mpeg.ts segments. In my opinion, CMAF using mp4 segments is over-rated, and heavily promoted by commercial encoding and streaming engines like Wowza.
> Regards,
> Alvaro Jiménez
>
>
> On Tuesday 11 October 2022 10:06:36 AM (-07:00), Stefan Oltmanns wrote:
>
>> Hi Clay,
>>
>> for me storage is not a major concern (the total number of videos will
>> not be that high), but device compatibility is (including older
>> devices). Apple does not seem to support CMAF on older devices, only
>> MPEG-TS, therefore I'll stick to MPEG-TS. There are also some approaches
>> like mux.js that are intended to remux the stream as needed in the
>> browser, but I rather stick to MP4/MPEG2-TS.
>>
>> I have not played with ffmpeg-python yet, but good to know. I started
>> writing a PHP script that generates a ffmpeg command-line for
>> transcoding a specific video (in fact multiple, because ffmpeg got
>> killed when I tried to transcode to all formats at once: my system ran
>> out of it's 64 GB memory...).
>>
>> I still couldn't figure out how generate a single DASH manifest for webm
>> and mp4 files. That should be possible, because dash.js added support
>> for that in 4.0 and shaka seems to have always supported that.
>>
>> Best regards
>> Stefan
>>
>>
>> Am 11.10.22 um 17:00 schrieb Clay via ffmpeg-user:
>>> Hi Steve
>>>
>>> Have you looked into CMAF for this solution?  I am also working on some
>>> complex transcoding and packaging actions for HLS ABR delivery.  I am
>>> looking into using CMAF to reduce the overall storage footprint (gpu/cpu
>>> threads still cost a lot more than storage).  Also, I am experimenting
>>> with ffmpeg-python (https://github.com/kkroening/ffmpeg-python), have
>>> you (or anyone reading this) played around with it?
>>>
>>> *I apologize to the forum for the accidental prior message (inadvertent
>>> click :-P)
>>>
>>> Liberty & Regard,
>>> Clay
>>>
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>>
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>