Black screen on certain HD channels

DJBenson · August 14, 2016 at 12:58 PM

Hi folks

I have a number of Kodi-based devices around my house on various platforms, all connecting to a TVHeadend backend providing DVB-T/2 and DVB-S/2 channels (alligned to the Sky UK EPG structure).

One client in particular is giving me grief - it's the LibreELEC client running on a new Raspberry Pi 3.

Certain channels (namely the BBC Olympic HD channels and CBeebies HD) return only a blank screen. I can see that data is being served to the client (via HTSP) from TVHeadend but no sound/video is displayed. If I show the stats overlay on top of the blank screen, it shows that Kodi is receiving data (including the bitrate of the stream) but there are no match/phase/pll stats for the channel.

Eventually, Kodi crashes and restarts but I can find nothing useful in the logs.

I'm running LibreELEC 7.0.2 and TVHeadend git-master (bang up to date). I don't think TVHeadend is the problem as if I use other Kodi clients (not LibreELEC) the channels work fine, same for streaming via mobile and the TVHeadend web UI.

I'm using omx hardware acceleration and I have deinterlace and deinterlace method both set to auto.

I've attached screenshots of a "good" HD stream and a "bad" one (both are FTA and both from Astra 28.2).

Please ignore the 'CBeebies HD has moved' EPG entry - that's coming from the EPG data for the DVB-T variant which I've unmapped now (whilst the Olympics are on the HD variant on DVB-T has been removed/scaled back).

paulio_h · August 16, 2016 at 8:56 AM

I'm having the same problem - I have a mixture of Pi1 B+ and PI2 machines all running LibreElec 7.0.2 and none of them will play CBeebies HD. I thought at first that it was something to do with the retune that happened recently but it seems to run fine on a Kodi instance running on Windows 7. My backend is running MythTv 0.27 and I'm using TBS cards to grab from Freesat so I thought perhaps there was an issue with the PVR addon, however I tried creating a short recording of CBeebies HD and again it runs fine on Kodi on Windows 7 but won't run on any of my PIs. The file also seems to run fine on VLC on windows so it doesn't look like there's anything particularly wrong with the file itself.

When I get a chance I'm going to try to grab some logs and other info. My 3yr old hasn't noticed that he's watching CBeebies in SD yet..

markius · August 19, 2016 at 12:02 AM

I'm glad this isn't just me.
I think there's something CODEC related that the RPi hardware acceleration doesn't like because if you turn OMXplayer or MMAL off (in Settings/Player/Video) the affected streams will actually play albeit very slowly.

EDIT: Here is the CODEC information from the stream that won't play

Code

[email]root@debian:/home/hts[/email]# mediainfo Olympics\ 2016\:\ Basketball.ts


General
ID                                       : 2043 (0x7FB)
Complete name                            : Olympics 2016: Basketball.ts
Format                                   : MPEG-TS
File size                                : 53.9 MiB
Duration                                 : 30s 696ms
Overall bit rate mode                    : Variable
Overall bit rate                         : 14.6 Mbps


Video
ID                                       : 512 (0x200)
Menu ID                                  : 1081 (0x439)
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : [email]High@L4.0[/email]
Format settings, CABAC                   : Yes
Format settings, ReFrames                : 4 frames
Format settings, GOP                     : M=4, N=12
Codec ID                                 : 27
Duration                                 : 30s 600ms
Bit rate                                 : 13.7 Mbps
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate                               : 25.000 fps
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Interlaced
Scan order                               : Top Field First
Bits/(Pixel*Frame)                       : 0.265
Stream size                              : 50.1 MiB (93%)
Color primaries                          : BT.709
Transfer characteristics                 : BT.709
Matrix coefficients                      : BT.709


Audio
ID                                       : 660 (0x294)
Menu ID                                  : 1081 (0x439)
Format                                   : MPEG Audio
Format version                           : Version 1
Format profile                           : Layer 2
Codec ID                                 : 4
Duration                                 : 30s 648ms
Bit rate mode                            : Constant
Bit rate                                 : 192 Kbps
Channel(s)                               : 2 channels
Sampling rate                            : 48.0 KHz
Compression mode                         : Lossy
Delay relative to video                  : -510ms
Stream size                              : 718 KiB (1%)
Language                                 : English


Menu
ID                                       : 256 (0x100)
Menu ID                                  : 1081 (0x439)
Duration                                 : 30s 696ms
List                                     : 512 (0x200) (AVC) / 660 (0x294) (MPEG Audio, English)
Language                                 :  / English
Service name                             : BBC Olym 1 HD
Service provider                         : BSkyB
Service type                             : advanced codec HD digital television

Display More

And this is from one that plays fine:

Code

[email]root@debian:/home/hts[/email]# mediainfo Olympics\ 2016.ts
General
ID                                       : 2050 (0x802)
Complete name                            : Olympics 2016.ts
Format                                   : MPEG-TS
File size                                : 13.0 MiB
Duration                                 : 12s 950ms
Overall bit rate mode                    : Variable
Overall bit rate                         : 8 279 Kbps


Video
ID                                       : 5400 (0x1518)
Menu ID                                  : 6941 (0x1B1D)
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : [email]High@L4.0[/email]
Format settings, CABAC                   : Yes
Format settings, ReFrames                : 4 frames
Format settings, GOP                     : M=8, N=24
Codec ID                                 : 27
Duration                                 : 12s 840ms
Bit rate                                 : 7 223 Kbps
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate                               : 25.000 fps
Standard                                 : Component
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : MBAFF
Scan order                               : Top Field First
Bits/(Pixel*Frame)                       : 0.139
Stream size                              : 11.1 MiB (85%)
Color primaries                          : BT.709
Transfer characteristics                 : BT.709
Matrix coefficients                      : BT.709


Audio #1
ID                                       : 5401 (0x1519)
Menu ID                                  : 6941 (0x1B1D)
Format                                   : AC-3
Format/Info                              : Audio Coding 3
Mode extension                           : CM (complete main)
Format settings, Endianness              : Big
Codec ID                                 : 129
Duration                                 : 12s 960ms
Bit rate mode                            : Constant
Bit rate                                 : 384 Kbps
Channel(s)                               : 6 channels
Channel positions                        : Front: L C R, Side: L R, LFE
Sampling rate                            : 48.0 KHz
Bit depth                                : 16 bits
Compression mode                         : Lossy
Delay relative to video                  : -475ms
Stream size                              : 608 KiB (5%)
Language                                 : English


Audio #2
ID                                       : 5402 (0x151A)
Menu ID                                  : 6941 (0x1B1D)
Format                                   : MPEG Audio
Format version                           : Version 1
Format profile                           : Layer 2
Codec ID                                 : 4
Duration                                 : 12s 936ms
Bit rate mode                            : Constant
Bit rate                                 : 256 Kbps
Channel(s)                               : 2 channels
Sampling rate                            : 48.0 KHz
Compression mode                         : Lossy
Delay relative to video                  : -452ms
Stream size                              : 404 KiB (3%)
Language                                 : nar


Text
ID                                       : 5404 (0x151C)
Menu ID                                  : 6941 (0x1B1D)
Format                                   : DVB Subtitle
Codec ID                                 : 6
Duration                                 : 12s 900ms
Delay relative to video                  : 2s 396ms
Language                                 : English


Menu
ID                                       : 260 (0x104)
Menu ID                                  : 6941 (0x1B1D)
Duration                                 : 12s 950ms
List                                     : 5400 (0x1518) (AVC) / 5402 (0x151A) (MPEG Audio, nar) / 5404 (0x151C) (DVB Subtitle, English) / 5401 (0x1519) (AC-3, English)
Language                                 :  / nar / English / English
Service name                             : BBC One HD
Service provider                         : BSkyB
Service type                             : advanced codec HD digital television

Display More

markius · August 21, 2016 at 10:26 PM

So popcornmix came up with a fix for this over at the RPi LibreElec thread: LibreELEC Testbuilds for RaspberryPi (Kodi 17.0)

Add the following to advancedsetting.xml

Code

<advancedsettings>
    <omx>
        <omxdecodestartwithvalidframe>0</omxdecodestartwithvalidframe>
    </omx>
</advancedsettings>

Worked for me on the Olympics HD streams. Just in time for the closing ceremony.

paulio_h · August 22, 2016 at 9:25 PM

Quote from markius
So popcornmix came up with a fix for this over at the RPi LibreElec thread: LibreELEC Testbuilds for RaspberryPi (Kodi 17.0)

Add the following to advancedsetting.xml
Code
<advancedsettings>
    <omx>
        <omxdecodestartwithvalidframe>0</omxdecodestartwithvalidframe>
    </omx>
</advancedsettings>
Worked for me on the Olympics HD streams. Just in time for the closing ceremony.

Superb. Works for CBeebies HD as well.