errors/glitches playing IPTV recorded stream (h264)

[Jose Oliver <primijos@…>]

Trying to watch a previously recorded stream or live-tv from an IPTV channel produces very choppy playback with lots of glitches/artifacts.

Channel URL correspond to rtp:// multicast, using udp:// in "url" column in iptv_channel (set by hand, since (that's another bug), mythtv doesn't populates it when scanning the .m3u file for channels).

The same stream, recorded by mythbackend, can be played from file without problems with mplayer and vlc. Trying to play the same file with ffplay causes also glitches/choppy image and, at some point, ffplay aborts/segfaults.

System is mythbuntu 12.04. Output of lsb_release -a: No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 12.04.3 LTS Release: 12.04 Codename: precise

HW: Xtreamer ultra, nvidia graphics card & propietary drivers.

Using VDPAU for video playback.

I'm also attaching a 1min sample of the stream recorded and the output for "mythavtest --loglevel debug -v all"

thanks in advance, Jose

[Jose Oliver <primijos@…>]

output of mythbackend --version

[Jose Oliver <primijos@…>]

output of mythavtest --loglevel debug -v all

[Jose Oliver <primijos@…>]

sample of the recorded data

[amlopezalonso@…]

Confirming here but your glitches are almost unnoticeable. In my case, there are clear pixelation issues every couple of seconds or so... I have to perform further testing though.

Regards, Antonio

[amlopezalonso@…]

As per the last comments in:

​http://www.mythtvtalk.com/can-mythtv-access-iptv-rtp-stream-not-freebox-14968/

it seems the issue may be in the BE rather than in the internal player. OTOH dev wagnerrp was then requesting a failing sample which reminds me this bug has not been assigned yet in five months to any dev. Maybe any other kind of sample/log reports is needed?

[amlopezalonso@…]

I have to retract from my comment above and definitely it seems to be an internal player issue. For testing purposes I recorded a few minutes of a program belonging to a Movistar TV (IPTV) channel and found the following:

1) Both LiveTV and the recording showed choppy video every couple of seconds (approx.). Audio was ok.

2) VLC has no issues watching both live IPTV and the MythTV recording.

3) Transcoding the recording (using "Autodetect from 1080i" profile) yields a recording with no choppiness at all.

Any suggestion to further testing this?

Regards, Antonio

[primijos@…]

Just to add some more info: I'm not quite sure this is only an internal player issue. Since IPTV is not working for me, and I'm now using 0.28 (devel), I've doing some experiments with the new "External Recorder" in order to feed IPTV streams to mythtv:

My first test was using udpxy to get the IPTV streams by using a ruby script as External Recorder. Myth was able to save the stream and playback was OK.

Please note that this has been just a single/simple test (less than a minute long video), and I've not tested LiveTV, just scheduled recording.

So, as mythtv is able to play the stream OK when feed as a simple TS through udpxy, I'm wondering whether this issue is a BE/Internal player combination. I mean: perhaps the BE, when extracting the TS from the RTP/UDP/Whatever packets, generates a not-so-beautiful-for-the-internal-player stream that, who knows why, VLC/mplayer can, some how, play?

In order to try this without External Recorder support, the best option would probably be just record an IPTV stream to file using vlc, udpxrec, mplayer, etc. and copy it over one of the mythtv recordings, to try to play it (or use mythavtest? I'm not sure about that, I believe that some tests I did at some point showed up mythavtest being able to play stream / stream types that the internal player wasn't able to play [raw (no HLS) hhttp streams?])

Just an idea.

Best, Jose

[amlopezalonso@…]

Jose@

Are you experiencing "unable to read the first 2048 bytes" errors most of the time when entering LiveTV (Movistar TV)? I have filed a new bug report on this matter.

[amlopezalonso@…]

Have to correct item 2) above, which should read:

2) VLC has no issues watching live IPTV but it does when playing MythTV recording.

Regards, Antonio

[primijos@…]

Log fragment dealing with MPEG structure issues while trying to record IPTV streams

[primijos@…]

I've added a sample log with some -perhaps- interesting messages when I tried to record IPTV Imagenio

[amlopezalonso@…]

BE log (level: debug; verbosity: network,playback)

[jpoet]

Do you guys have your NIC set to promiscuous mode? For multicast that is recommended.

As far as logging goes, setting "-v channel,record" is typically the best mode even for IPTV stuff. "-v network" mostly just shows the communication between the various MythTV components.

[amlopezalonso@…]

BE log (level: debug; verbosity: channel,record)

[amlopezalonso@…]

Thanks for your suggestions. Alas turning promiscuous mode on seems to have no effect upon the choppiness.

Regarding channel/record verbosity, please find new BE log attached.

[amlopezalonso@…]

Could it be this choppy playback is related to the "2048 bytes" error I reported yesterday as ticket #12188? It seems to be a buffering problem leading to pixelation IMHO.

[Thomas Meyer <thomas--meyer@…>]

Hi,

I installed a new HTPC with mythbuntu 14.10. I configured it for IPTV "Entertain" of Deutsche Telekom. While watching a recorded TV show or live TV, there are every one or two minutes block artifacts - sometimes only in a small region, sometimes in the whole picture. Playing the file with vlc produces the same result, and the artifacts show always in the same point in time and region of the picture. Watching live TV with vlc works fine. Seems to be the same problem as described in this bug report. The last comment is 7 months old...do you still investigate this?

Kind regards, Thomas

[mbt2015@…]

I'm having the same problem with Austrian A1 TV.

I believe that this is due to using udp:// instead of rtp:// (which is a workaround for #11852). See also ticket:11852#comment:13.

[mbt2015@…]

Remark: There is now no need any more to change rtp:// to udp:// as #11852 has been fixed. When using rtp:// URLs for A1 TV the errors/glitches are gone (same for Deutsche Telekom probably). I think this issue can get closed.

[Karl Egly]

Jose, can you verify that #11852 fixes your issue? (update to latest fixes/0.27 and change the urls back to rtp:// )

[Karl Egly]

I'm closing this as presumed fixed. Reopen if this is not the case.