GStreamer with MPEG-TS Video4Linux ATSC/DVB Recording

Question

I'm having an impossible time setting up a filtergraph to read from a recording that I made from my DVB video4linux device. Any help would be vastly appreciated.

How I made the recording:

To tune the channel:

azap -c ~/channels.conf "Florida"

To record the channel:

cat /dev/dvb/adapter0/dvr0 > /tmp/test

This is the way that recordings must be made (I can not use any GST DVB plugins to do this for me).

I used tstools to identify that the recording is a TS stream:

tstools/bin$ ./stream_type ~/recordings/20130129-202049
Reading from /home/dustin/recordings/20130129-202049
It appears to be Transport Stream

...but that there are no PAT/PMT frames:

tstools/bin$ ./tsinfo ~/recordings/20130129-202049
Reading from /home/dustin/recordings/20130129-202049
Scanning 10000 TS packets

Found 0 PAT packets and 0 PMT packets in 10000 TS packets

I was able to produce a single ES (elementary stream) stream, by running ts2es:

tstools/bin$ ./ts2es -pid 97 ~/recordings/20130129-202049 ~/recordings/20130129-202049.es
Reading from /home/dustin/recordings/20130129-202049
Writing to   /home/dustin/recordings/20130129-202049.es
Extracting packets for PID 0061 (97)
!!! 4 bytes ignored at end of file - not enough to make a TS packet
Extracted 219258 of 248113 TS packets

I am able to play the ES stream (even though the video is frozen on the first frame):

gst-launch-0.10 filesrc location=~/recordings/20130129-202049.es ! decodebin2 ! autovideosink
gst-launch-0.10 filesrc location=~/recordings/20130129-202049.es ! decodebin2 ! xvimagesink
gst-launch-0.10 playbin2 uri=file:///home/dustin/recordings/20130129-202049.es

No matter what I do, though, I can't get the original TS file to open. However, it opens in Mplayer/FFMPEG, perfectly (but not VLC). This is the output of FFMPEG:

ffmpeg -i 20130129-202049

ffmpeg version 0.8.5-4:0.8.5-0ubuntu0.12.04.1, Copyright (c) 2000-2012 the Libav developers
  built on Jan 24 2013 18:03:14 with gcc 4.6.3
*** THIS PROGRAM IS DEPRECATED ***
This program is only provided for compatibility and will be removed in a future release. Please use avconv instead.
[mpeg2video @ 0x9be7be0] mpeg_decode_postinit() failure
    Last message repeated 4 times
[mpegts @ 0x9be3aa0] max_analyze_duration reached
[mpegts @ 0x9be3aa0] PES packet size mismatch
Input #0, mpegts, from '20130129-202049':
  Duration: 00:03:39.99, start: 9204.168844, bitrate: 1696 kb/s
    Stream #0.0[0x61]: Video: mpeg2video (Main), yuv420p, 528x480 [PAR 40:33 DAR 4:3], 15000 kb/s, 30.57 fps, 29.97 tbr, 90k tbn, 59.94 tbc
    Stream #0.1[0x64]: Audio: ac3, 48000 Hz, stereo, s16, 192 kb/s
At least one output file must be specified

This tells us that the video stream has PID 0x61 (97).

I have been trying for a few days, so the following are only examples of a couple of attempts. I'll provide the playbin2 example first, since I know that thousands of people will respond, insisting that I just use that. It doesn't work.

gst-launch-0.10 playbin2 uri=file:///home/dustin/recordings/20130129-202049

Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
ERROR: from element /GstPlayBin2:playbin20/GstURIDecodeBin:uridecodebin0/GstDecodeBin2:decodebin20/GstMpegTSDemux:mpegtsdemux0: Could not determine type of stream.
Additional debug info:
gstmpegtsdemux.c(2931): gst_mpegts_demux_sink_event (): /GstPlayBin2:playbin20/GstURIDecodeBin:uridecodebin0/GstDecodeBin2:decodebin20/GstMpegTSDemux:mpegtsdemux0:
No valid streams found at EOS
ERROR: pipeline doesn't want to preroll.
Setting pipeline to NULL ...
Freeing pipeline ...

It fails [probably] because no PID has been specified with which to find the video (the "EOS" error, I think).

Naturally, I tried the following to start by demuxing the TS format. I believe it's the "es-pids" property that receives the PID in the absence of PMT information (which tstools said there weren't any, above), but I tried "program-number", too, just in case. gst-inspect indicates that one is hex and the other is decimal:

gst-launch-0.10 -v filesrc location=20130129-202049 ! mpegtsdemux es-pids=0x61 ! fakesink
gst-launch-0.10 -v filesrc location=20130129-202049 ! mpegtsdemux program-number=97 ! fakesink

Output:

gst-launch-0.10 filesrc location=20130129-202049 ! mpegtsdemux es-pids=0x61 ! fakesink
Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
ERROR: from element /GstPipeline:pipeline0/GstMpegTSDemux:mpegtsdemux0: Could not determine type of stream.
Additional debug info:
gstmpegtsdemux.c(2931): gst_mpegts_demux_sink_event (): /GstPipeline:pipeline0/GstMpegTSDemux:mpegtsdemux0:
No valid streams found at EOS
ERROR: pipeline doesn't want to preroll.
Setting pipeline to NULL ...
Freeing pipeline ...
dustin@dustinmicro:~/recordings$ gst-launch-0.10 -v filesrc location=20130129-202049 ! mpegtsdemux es-pids=0x61 ! fakesink
Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
ERROR: from element /GstPipeline:pipeline0/GstMpegTSDemux:mpegtsdemux0: Could not determine type of stream.
Additional debug info:
gstmpegtsdemux.c(2931): gst_mpegts_demux_sink_event (): /GstPipeline:pipeline0/GstMpegTSDemux:mpegtsdemux0:
No valid streams found at EOS
ERROR: pipeline doesn't want to preroll.
Setting pipeline to NULL ...
Freeing pipeline ...
dustin@dustinmicro:~/recordings$ gst-launch-0.10 -v filesrc location=20130129-202049 ! mpegtsdemux es-pids=0x61 ! fakesink
Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
ERROR: from element /GstPipeline:pipeline0/GstMpegTSDemux:mpegtsdemux0: Could not determine type of stream.
Additional debug info:
gstmpegtsdemux.c(2931): gst_mpegts_demux_sink_event (): /GstPipeline:pipeline0/GstMpegTSDemux:mpegtsdemux0:
No valid streams found at EOS
ERROR: pipeline doesn't want to preroll.
Setting pipeline to NULL ...
Freeing pipeline ...

However, when I try mpegpsdemux (for program streams (PS), as opposed to transport streams (TS)), I get further:

gst-launch-0.10 filesrc location=20130129-202049 ! mpegpsdemux ! fakesink

Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...

(gst-launch-0.10:14805): GStreamer-CRITICAL **: gst_event_new_new_segment_full: assertion `position != -1' failed

(gst-launch-0.10:14805): GStreamer-CRITICAL **: gst_mini_object_ref: assertion `mini_object != NULL' failed

(gst-launch-0.10:14805): GStreamer-CRITICAL **: gst_pad_push_event: assertion `event != NULL' failed
Pipeline is PREROLLED ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock

(gst-launch-0.10:14805): GStreamer-CRITICAL **: gst_event_new_new_segment_full: assertion `position != -1' failed

(gst-launch-0.10:14805): GStreamer-CRITICAL **: gst_mini_object_ref: assertion `mini_object != NULL' failed

(gst-launch-0.10:14805): GStreamer-CRITICAL **: gst_pad_push_event: assertion `event != NULL' failed

(gst-launch-0.10:14805): GStreamer-CRITICAL **: gst_event_new_new_segment_full: assertion `position != -1' failed

(gst-launch-0.10:14805): GStreamer-CRITICAL **: gst_mini_object_ref: assertion `mini_object != NULL' failed

(gst-launch-0.10:14805): GStreamer-CRITICAL **: gst_pad_push_event: assertion `event != NULL' failed

(gst-launch-0.10:14805): GStreamer-CRITICAL **: gst_event_new_new_segment_full: assertion `position != -1' failed

(gst-launch-0.10:14805): GStreamer-CRITICAL **: gst_mini_object_ref: assertion `mini_object != NULL' failed

(gst-launch-0.10:14805): GStreamer-CRITICAL **: gst_pad_push_event: assertion `event != NULL' failed


...


Got EOS from element "pipeline0".
Execution ended after 1654760008 ns.
Setting pipeline to PAUSED ...
Setting pipeline to READY ...
Setting pipeline to NULL ...
Freeing pipeline ...

I'll still get the same problem whenever I use the mpegtsdemux, even if it follows mpegpsdemux, above.

I don't understand this, since I haven't even picked a PID yet.

What am I doing wrong?

Dustin

Answer 1

Bingo.

It turns out that this issue was primarily caused by the invalid frames typical of MPEG-TS broadcast streams. By first running the TS file through mencoder to reconstruct it (no reencode), playbin2 suddenly worked:

mencoder 20130129-202049 -oac copy -ovc copy -o 20130129-202049.copy

As I've been told by the authors of the mpegtsdemux, flutsdemux is newer, and should be preferred over the older mpegtsdemux. flutsdemux may also handle these malformed frames better.

EDIT

Unfortunately, this was incorrect. mencoder, although being instructed to -copy- the stream, repackages it as an AVI, rather than keeping it as MPEGTS:

$ gst-discoverer-1.0 ~/capture_0051_WXEL.dvb.distill
Analyzing file:///home/dustin/capture_0051_WXEL.dvb.distill
Done discovering file:///home/dustin/capture_0051_WXEL.dvb.distill

Topology:
  container: Audio Video Interleave (AVI)
    audio: AC-3 (ATSC A/52)
    video: MPEG-2 Video

Properties:
  Duration: 0:00:12.696016666
  Seekable: yes
  Tags: 
      encoder: MEncoder svn r34540 (Ubuntu), built with gcc-4.7
      container format: AVI
      audio codec: AC-3 audio
      bitrate: 384000
      video codec: MPEG 2 Video

That being said, it looks like PMT packets are not present when I record from off the air. mplayer/mencoder seem to cope with this, whereas GStreamer and VLC choke on the data. When I used the same device to record an ATSC/NTSC cable feed, the PMT packets were there as expected. You can determine the presence of certain packet types using "tsreport" from the "tstools" package:

The OTA feed:

$ tsreport -v capture_20130621-0402.trunc | grep PMT
!!! 60 bytes ignored at end of file - not enough to make a TS packet

The cable feed:

$ tsreport -v capture_20130621-1118.ntsc.qam256.Florida.dvb | grep PMT
   31960: TS Packet 171 PID 0230 [pusi] PMT
   73508: TS Packet 392 PID 0230 [pusi] PMT
  101520: TS Packet 541 PID 0230 [pusi] PMT
  164688: TS Packet 877 PID 0230 [pusi] PMT

Hopefully this saves someone some time. It took enough of mine.