[FFmpeg-devel] [PATCH] avformat/mpegts.c: reduce buffering during initialization

[Andriy Gelman]

> What is the issue that you are seeing and that this patch fix? Is it only
> matters for low bitrate mpegts? (like 64 kbps streams?) Or does this
> improve high bitrate streams as well somehow?

I'm muxing hevc video + very low bitrate binary messages into mpegts.
If the hevc video is not present, I would have to buffer 8192 bytes of
binary messages to get past mpegts_read_header, which was creating a large
latency.
This patch reduces the startup time. As you mentioned, it does not apply to
high bitrate streams.

Also in git history, I saw that the size of the buffer was changed in
ad-hoc way from 1024 -> 5*1024-> 8 * 1024 because I assume probing failed
in some cases.
I feel that the proposed patch would be a better solution as it follows the
same ideas when probing for unknown parameters in other parts of the code.

Regards,
Andriy


On Tue, 5 Mar 2019 at 11:59, Marton Balint <cus at passwd.hu> wrote:

>
>
> On Mon, 4 Mar 2019, andriy.gelman at gmail.com wrote:
>
> > From: Andriy Gelman <andriy.gelman at gmail.com>
> >
> > Reduces buffering during estimation of mpegts raw_packet_size
> > parameter. Instead of buffering a fixed 8192 bytes, calculate
> > probe scores on a smaller buffer. Increase buffer size until
> > probe score is greater than minimum value.
>
> What is the issue that you are seeing and that this patch fix? Is it only
> matters for low bitrate mpegts? (like 64 kbps streams?) Or does this
> improve high bitrate streams as well somehow?
>
> Thanks,
> Marton
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