[vlc-devel] Frames being dropped while while trying ABR streaming locally

[Steve Lhomme]

On 2020-01-16 17:47, Aniketh Girish wrote:
> Hi all,
> 
> I have been working on analysing the adaptive module of VLC.
> 
> Currently, I hosted all the segments and manifest created for both DASH 
> and HLS. Then I use the manifest/playlist to stream with VLC. Since I'm 
> streaming either with DASH or HLS from the server I have locally, I 
> expect no network-related latency or bandwidth problem to occur and thus 
> I expect a stream with the highest quality seamlessly.
> 
> But then, I get a log while streaming like this[1] along with quite a 
> lot of *video* frames being dropped. Yes, it was just the video frames, 
> I didn't experience any audio frames being dropped at all. Even, I 
> collected the stats, it only proved that video frames are the only ones 
> being dropped.
> 
> Though the debug message mentions that the frame loss might be due to 
> slower hardware, but then I'm using an i7 core CPU with 12GB of RAM with 
> 8GB of GPU as well. So I'm not exactly sure if that is the reason either.

The logs show your system is too slow to decode the video you're 
playing. It doesn't have much to do with the streaming protocol. What 
kind of content are you trying to play with what hardware and what 
hardware decoder or software decoder is used ? If you provide the full 
logs we have all these information.

> Things did to analyse this issue, but resulted in me again experiencing 
> the frame loss:
> 
>  1. Tried different web server software (Used caddy as well as Apache to
>     serve the segments). I experienced dropping of frames with both the
>     servers.
>  2. Tried different encoding schemes for segmentation for both DASH and
>     HLS.
>  3. Streamed an mp4 file directly through `http://` which was served in
>     the local webserver to see if there were any frames dropped.
> 
> It would be great if you could take a look into this issue and confirm 
> if this problem exists/this issue is reproducible at first. If not, 
> please do let me know if there is a way we can solve this. Else, if it 
> is a bug, we can try to fix it then :D

Now as it is adaptive streaming, if the hardware is not capable of 
decoding something properly we should use an easier version to decode. 
But I'm not sure that something we (can) support yet.

> [1]: https://pastebin.com/idUnJK3N
> -- 
> Aniketh Girish
> Member at FOSS at Amrita <http://foss.amrita.ac.in/>
> Amrita University <http://amrita.edu>
> <https://github.com/Aniketh01>Github <https://github.com/Aniketh01> | 
> GitLab <https://gitlab.com/Aniketh01/> | Blog 
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> 
> /"For the Love of Code."
> 
> 
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