mpegpsdemux: Unable to play backward

How to reproduce:

gst-play-1.0 medias/defaults/mpegps/sample_mpeg_program_stream_scr.mpg

and then press the key "d" to play reverse

Results:

Reverse playback is not working where no frame will be decoded.

Analysis:

After some investigations, no i-frame is sent by mpegpsdemux/mpegvideoparser, so the decoder does not decode anything. It receives only b-frame. This media is using a non zero SCR.