Trick mode: backward play is not happening for WMV

[Tim-Philipp Müller]

On Tue, 2013-03-12 at 10:41 +0000, amit.debnath at wipro.com wrote:

Hi,

> I am trying to implement trick mode backward play with gstreamer.
> 
> OS: Ubuntu 10.04. 

This Ubuntu version uses a GStreamer version from 3-years ago...

> File type : .wmv file.
> 
> I am trying to use the following method:
> 
> 1. Getting position by calling gst_element_query_position().
> 
> 2. Then passing different play rate to the API gst_event_new_seek()
> for playing in different speed.. 
> 
> if (play_rate > 0)
> { 
> seek_event = gst_event_new_seek ((gdouble)play_rate, GST_FORMAT_TIME,
> (GstSeekFlags)(GST_SEEK_FLAG_ACCURATE|GST_SEEK_FLAG_FLUSH),
> GST_SEEK_TYPE_SET, position, GST_SEEK_TYPE_NONE, 0);
> }
> else
> {
> seek_event = gst_event_new_seek (play_rate, GST_FORMAT_TIME,
> (GstSeekFlags)(GST_SEEK_FLAG_ACCURATE|GST_SEEK_FLAG_FLUSH),
> GST_SEEK_TYPE_SET, 0, GST_SEEK_TYPE_SET, position);
> }
> 
> In my case when the play_rate is >1, fast forward is happening
> nicely. 
> 
> But every time I am trying with any negative value, the backward play
> is not happening.
> 
> The event is not returning any error as well. The play is happening
> with the previous speed set. 

This is not supported yet by the ASF demuxer. Reverse playback is
disabled even in the most recent versions.

Someone needs to implement this.

Cheers
 -Tim