typefinding: some mpeg files are not identified as mpeg files

Bug #1012652 reported by Joe on 2012-06-13
16
This bug affects 3 people
Affects Status Importance Assigned to Milestone
GStreamer
New
Undecided
Unassigned

Bug Description

When dealing with mpeg files in Ubuntu 12.04, Totem will not play nor show a
Thumbnail in Nautilus for some mpeg files. Some mpeg files are playable and
have a Thumbnail, but others are not. There is no difference between playable
and non-playable files with respect to how they were created, the size of the
file, the type of content, etc.

It can be verified running the following command on the sample attached:
$ gst-typefind <clip>

The reason is that typefind function scans the first 128k of the clip and
tries to find several PES packets. In playable clips there's audio muxed
at the beginning of clips which uses small PES packets and the identity
conditions can be satisfied.

In both playable and non-playable clips, there's something quite unusual as
there's a single Program
Stream packet per video frame, that means that some of them are as big as
64K and the conditions to identify the clip are not satisfied.

I can't tell if this clip wrongly muxed because I haven't checked on the
spec but usually a video frame in mpeg PS is split in fragments of about 2K.

The issue is in the typefind function.

(all mpeg files that are non-playable in Totem are correctly identified as mpeg
files, and playable, by video player VLC.)

Revision history for this message
Joe (gsbbj) wrote :

Not sure how to connect this ubuntu bug report to the gnome/gstreamer bug I created: https://bugzilla.gnome.org/show_bug.cgi?id=678011

Revision history for this message
Michael Sheldon (michael-sheldon) wrote :

This isn't really related to gst-opencv (which purely focuses on computer vision in gstreamer) so I've reassigned it.

affects: gst-opencv → gstreamer
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