[Bug 761086] New: splitmuxsrc: use the max ts of all streams as the offset to align the next stream with

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=761086

Bug ID: 761086
Summary: splitmuxsrc: use the max ts of all streams as the
offset to align the next stream with
Classification: Platform
Product: GStreamer
Version: git master
OS: Linux
Status: NEW
Severity: normal
Priority: Normal
Component: gst-plugins-good
Assignee: gstreamer-***@lists.freedesktop.org
Reporter: ***@collabora.com
QA Contact: gstreamer-***@lists.freedesktop.org
GNOME version: ---

Created attachment 319684
--> https://bugzilla.gnome.org/attachment.cgi?id=319684&action=edit
splitmuxsrc: use the max ts of all streams as the offset to align the next
stream with

Splitmuxsrc currently finds and uses the minimum timestamp of all streams
(audio/video/subtitle) as the first timestamp for the next part, but this is
incorrect and gets noticed when you have subtitles, which are sparse. (In
audio/video cases it can easily go unnoticed because the ending timestamps are
very close together)

So for example if the current part ends at t=5s and the last subtitle was at
t=1s, then the next part's timestamps start from t=1s and you lose 4 seconds of
data in the output.

The attached patch fixes the issue.

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=761086

Jan Schmidt <***@noraisin.net> changed:

What |Removed |Added
----------------------------------------------------------------------------
CC| |***@noraisin.net

--- Comment #1 from Jan Schmidt <***@noraisin.net> ---
I only just noticed this bug. Using the max of all timestamps is not correct,
and pretty much guarantees that there'll be a gap in the audio or video
timelines, which are supposed to be seamless.

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=761086

--- Comment #2 from George Kiagiadakis <***@tolabaki.gr> ---
I was just looking at this again. You are right, it makes sense to use the min
of all timestamps, but there should be a way to exclude sparse streams from the
calculation.

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=761086

--- Comment #3 from Jan Schmidt <***@noraisin.net> ---
I agree. Basing it on the stream-start event sparse flag should work. I think
that's widely enough implemented.

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=761086

George Kiagiadakis <***@tolabaki.gr> changed:

What |Removed |Added
----------------------------------------------------------------------------
Attachment #319684|0 |1
is obsolete| |

--- Comment #4 from George Kiagiadakis <***@tolabaki.gr> ---
Created attachment 346554
--> https://bugzilla.gnome.org/attachment.cgi?id=346554&action=edit
splitmuxpartreader: identify sparse streams

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=761086

--- Comment #5 from George Kiagiadakis <***@tolabaki.gr> ---
Created attachment 346555
--> https://bugzilla.gnome.org/attachment.cgi?id=346555&action=edit
splitmuxpartreader: ignore sparse streams when calculating the end offset of a
part

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=761086

--- Comment #6 from George Kiagiadakis <***@tolabaki.gr> ---
Created attachment 346556
--> https://bugzilla.gnome.org/attachment.cgi?id=346556&action=edit
tests: splitmux: add unit test for content with sparse streams

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=761086

Jan Schmidt <***@noraisin.net> changed:

What |Removed |Added
----------------------------------------------------------------------------
Attachment #346554|none |accepted-commit_now
status| |

--- Comment #7 from Jan Schmidt <***@noraisin.net> ---
Review of attachment 346554:
--> (https://bugzilla.gnome.org/review?bug=761086&attachment=346554)

Looks good

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=761086

Jan Schmidt <***@noraisin.net> changed:

What |Removed |Added
----------------------------------------------------------------------------
Attachment #346555|none |accepted-commit_now
status| |

--- Comment #8 from Jan Schmidt <***@noraisin.net> ---
Review of attachment 346555:
--> (https://bugzilla.gnome.org/review?bug=761086&attachment=346555)

Looks good

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=761086

Jan Schmidt <***@noraisin.net> changed:

What |Removed |Added
----------------------------------------------------------------------------
Attachment #346556|none |accepted-commit_now
status| |

--- Comment #9 from Jan Schmidt <***@noraisin.net> ---
Review of attachment 346556:
--> (https://bugzilla.gnome.org/review?bug=761086&attachment=346556)

Awesome, thanks!

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=761086

George Kiagiadakis <***@tolabaki.gr> changed:

What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution|--- |FIXED

--- Comment #10 from George Kiagiadakis <***@tolabaki.gr> ---
commit e6bd2a5c180958f74d58549ac8786e8e5584bd37
Author: George Kiagiadakis <***@collabora.com>
Date: Thu Feb 23 12:11:15 2017 +0200

tests: splitmux: add unit test for content with sparse streams

https://bugzilla.gnome.org/show_bug.cgi?id=761086

commit 9b845133377275e0e218f878d739b3869efc7510
Author: George Kiagiadakis <***@collabora.com>
Date: Wed Feb 22 11:23:19 2017 +0200

splitmuxpartreader: ignore sparse streams when calculating the end offset
of a part

A sparse stream's ending timestamp can be considerably smaller
than the ending timestamps of the other streams, which can lead
to skipping considerable time from the next part.

https://bugzilla.gnome.org/show_bug.cgi?id=761086

commit 99728792cde38ac6cd2cc30d84d5aede84b50c04
Author: George Kiagiadakis <***@collabora.com>
Date: Wed Feb 22 11:21:06 2017 +0200

splitmuxpartreader: identify sparse streams

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=761086

George Kiagiadakis <***@tolabaki.gr> changed:

What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|git master |1.11.3