On Leap 42.2 we���ve been unable to play MPEG videos such as,

Front.mpg: MPEG sequence, v1, progressive Y'CbCr 4:2:0 video, LD-TV 640P, 4:3,
29.97 fps
High_Speed.mpg: MPEG sequence, v2, program multiplex

$ gst-discoverer-1.0 Front.mpg

Analyzing file:///home/jason/Desktop/Front.mpg
Done discovering file:///home/jason/Desktop/Front.mpg
An error was encountered while discovering the file
 No valid frames decoded before end of stream

And I believe, this is the plugin that should provide support,
gstreamer-plugins-bad-1.8.3-5.5.4.x86_64
ffmpeg-3.3-6.8.1.x86_64

whereas, on Leap 42.1,

$ gst-discoverer-1.0 Front.mpg
Analyzing file:///home/jason/Front.mpg
Done discovering file:///home/jason/Front.mpg

Topology:
  video: MPEG-1 Video

Properties:
  Duration: 0:00:15.907000000
  Seekable: yes
  Tags:
      video codec: MPEG-1 Video
      bitrate: 12450509

$ gst-discoverer-1.0 High_Speed.mpg
Analyzing file:///home/jason/High_Speed.mpg
Done discovering file:///home/jason/High_Speed.mpg

Topology:
  container: MPEG-2 System Stream
    audio: MPEG-1 Layer 2 (MP2)
    video: MPEG-2 Video (Main Profile)

Properties:
  Duration: 0:00:21.720000000
  Seekable: yes
  Tags:
      audio codec: MPEG-1 Audio
      has crc: false
      channel mode: stereo
      nominal bitrate: 256000
      bitrate: 256000
      video codec: MPEG-2 Video

gstreamer-plugins-bad-1.8.2-113.1.x86_64
ffmpeg-3.1.1-82.1.x86_64


On Leap 42.2, gst debug shows,

0:00:00.363383039  2683 0x7fa258002000 WARN            videodecoder
gstvideodecoder.c:1167:gst_video_decoder_sink_event_default:<avdec_mpeg2_cuvid0>
error: No valid frames decoded before end of stream
0:00:00.363387785  2683 0x7fa258002000 WARN            videodecoder
gstvideodecoder.c:1167:gst_video_decoder_sink_event_default:<avdec_mpeg2_cuvid0>
error: no valid frames found
0:00:00.363404380  2683 0x7fa258002000 INFO        GST_ERROR_SYSTEM
gstelement.c:1879:gst_element_message_full:<avdec_mpeg2_cuvid0> posting
message: No valid frames decoded before end of stream
0:00:00.363433263  2683 0x7fa258002000 INFO        GST_ERROR_SYSTEM
gstelement.c:1902:gst_element_message_full:<avdec_mpeg2_cuvid0> posted error
message: No valid frames decoded before end of stream
0:00:00.363460628  2683      0x2485b20 WARN              discoverer
gstdiscoverer.c:1321:handle_message:<avdec_mpeg2_cuvid0> Got an error
[debug:gstvideodecoder.c(1167): gst_video_decoder_sink_event_default ():
/GstPipeline:Discoverer/GstURIDecodeBin:discoverer-uri/GstDecodeBin:decodebin1/avdec_mpeg2_cuvid:avdec_mpeg2_cuvid0:

Whereas on Leap 42.1, the gst_video_decoder is "avdec_mpeg2video".