On HD HEVC H.265 DVB-S2 channels picture become interlaced in 50% cases

[Sergey]

I am continue to describe software bug with common reason, which I have started here viewtopic.php?f=74&t=9496

Look to attachments.
When I just switch to HD HEVC H.265 DVB-S2 channel, picture can be normal HD quality in 50% cases and can be interlaced in 50% cases.
I have checked this issue on two different Loewe TV (bild 3.43).
This is really bad software bug, because it is corrupting my eyes, when I look to interlaced picture.

It is possible to eliminate interlacing in 50% cases if I will switch to UHD H.265 channel and back to HD H.265 channel.

[Sergey]

Well, a week is gone and no one answer!
Did Loewe assigned tracking number for this case?

This problem exist not only on HD (1080i) HEVC H.265 DVB-S2 channels, but also on SD (576i) HEVC H.265 DVB-S2 channels.
Look video DR+ in attachment with interlaced effect.
You just need to unpack Video-576i-H265-DR+.zip file to "Video DR+" folder on your HDD and open it on DR+ archive on any Loewe TV. I hope, there is no restrictions for this. In 50% cases of starting play this video, you will see interlaced effect.

Also it is possible to open video source file "00000052" from Video-576i-H265-DR+.zip file in VLC player on PC and you will see, that there is no interlaced effect at all.

And at the attachment picture is seen miniature of this video in DR+ archive. Looks good, isn't?

[nerdlicht]

First of all, thank you for providing some sample footage of your problem. Nobody is able to reproduce the effect, because this is linked to your Russian TV station. That's why nobody is answering.

I took a close look to your video file and I observed the following:

1. You can't "inject" a DR+ recording into another archive. But I took the transportstream and played it via the internal media player. It was not really a surprise but I can confirm the effect with interlace files. A quick workaround is to stop the playback and start again, then you have your described 50% chance to start with the right frame and the picture is like it should be.
2. Even VLC has problems with your file. For VLC it is a 288p file, so it is extremely squeezed. I forced the playback to 16:9 and it worked, but I had still some issues with the picture quality regarding the interlace decoding.
3. Now I took an even closer look into the file.
   Bildschirmfoto 2018-08-20 um 11.13.10.png
   The interns showing no signs of a interlaced file. For any player it is just a strange or at least unusual 720x288p file. A correct interlaced video should look like this:
   Bildschirmfoto 2018-08-20 um 11.13.53.png
   As you can see there are included informations about the scan type. In this case the top field has to be displayed first.
   
   Going back to your file I assume that the Loewe is trying is best and is just guessing the missing information. Sometimes it is starting with the first field of the interlace picture, sometimes with the second. The chance is 50:50, at least you have a picture out of this "corrupted" stream.

In my opinion your TV station is not coding the stream according to the standard. The file is very strange. We have 2018 and they combining a modern H.265 compression with interlace and an old analog color space. Extremely unusual. It is so rare, that you can't expect a fix from Loewe to fix the problems on the broadcasting side.

By the way, I travel a lot and sometimes I can observe your effect also on other TVs. It happens when old hotel networks were combined with modern TVs. Often they use interlaced streams in these hotels to broadcast the signal to the rooms. Actual crisp & sharp TVs don't know how to handle this stuff and showing exactly the same picture like yours.

[Sergey]

@nerdlicht, thank you very much for such full answer!

My comments:

Even VLC has problems with your file. For VLC it is a 288p file, so it is extremely squeezed. I forced the playback to 16:9 and it worked, but I had still some issues with the picture quality regarding the interlace decoding.

I agree, it is strange, that for VLC it is a 288p file, and I also forced the playback to 16:9, but I hadn't see any other issues.

Going back to your file I assume that the Loewe is trying is best and is just guessing the missing information. Sometimes it is starting with the first field of the interlace picture, sometimes with the second. The chance is 50:50, at least you have a picture out of this "corrupted" stream.

If chance to see interlaced effect is really 50%, then how you can explain next:
- if I switch between any channel (H.264 or H.265 non UHD) and 576i H.265 DVB-S2 channel, then sometime I can switch even 20 times and picture on 576i H.265 DVB-S2 channel remains with interlaced effect. And sometime I can switch even 20 times and picture on 576i H.265 DVB-S2 channel remains without interlaced effect.
- but if I switch between any UHD channel and 576i H.265 DVB-S2 channel, then really 50% chance to see interlaced effect.

In my opinion your TV station is not coding the stream according to the standard.

This TV station has more than 1 000 000 subscribers. I am tryed to find in internet the same issue - no results!
Do you really think, that this is not Loewe problem?

What I really don't understand, it is why no one asked me to record DR+ video or to record transport stream via service menu?
And why Loewe CCC still doesn't answer to me? I think, it is not normal to leave message to CCC without answer within a week.

I also recorded transport stream via service menu (look in attachment). Maybe it will helps more.

[nerdlicht]

I agree, it is strange, that for VLC it is a 288p file, and I also forced the playback to 16:9, but I hadn't see any other issues.

You can see it in the station logo, especially when you pause the picture. Anyway, it is not normal to force some output...

If chance to see interlaced effect is really 50%, then how you can explain next: ...

Well, I'm not an expert in probability theory and i don't know what technically happens during channel switching, but if I pause the picture - instead of switching - and start playback again, the chances are quite 50% to have a correct picture.

This TV station has more than 1 000 000 subscribers. I am tryed to find in internet the same issue - no results!

It only looks like a high numbers of viewers that might experience the same issue. I guess the majority of them using the setup box provided by the broadcasting company, which probably knows there own strange signal best.
Then you need a display with a high resolution to see the effect (which is btw only visible on rounded lines with high contrast like on the station logo).
But the most important thing: not many people look on their TV with such a technical view, most of them consuming just the content. They don't even notice this issue and if so, they maybe don't care.

Sergey, it's just an explanation, why there are no complaints, but you are right, it looks awkward. But I still think, that the stream your TV station is coding, is not a standard one. It is working on the Russian market with there own devices and so the only way to find a solution is with your dealer and Loewe in Russia.

And why Loewe CCC still doesn't answer to me? I think, it is not normal to leave message to CCC without answer within a week.

I don't know. I'm not related to Loewe in any kind.

[Sergey]

Then you need a display with a high resolution to see the effect (which is btw only visible on rounded lines with high contrast like on the station logo).

Station logo - is just most visible place of interlaced effect. Most important problem is that picture is flickering and it is corrupting my eyes, when I look to interlaced picture. So, I can't use Loewe bild for watching these channels.

But the most important thing: not many people look on their TV with such a technical view, ...

I agree, I am not ordinary customer.
But I thought, that Loewe must be happy, if I pick them to software bugs. Now I am not sure...

Sergey, it's just an explanation, why there are no complaints, but you are right, it looks awkward. But I still think, that the stream your TV station is coding, is not a standard one. It is working on the Russian market with there own devices and so the only way to find a solution is with your dealer and Loewe in Russia.

I don't understand how national satellite TV provider can make not standard coding.
I already talked with my dealer and with local Loewe service center. I am waiting for solution.
But I am sure, that they cannot do anything with this problem and this is Loewe software problem. That's why I am writing here.

I'm not related to Loewe in any kind.

I know it.

[Rudi16]

The interns showing no signs of a interlaced file.

It does not show any signs of a progressive video either. Maybe the stream lacks the "Field indication" SEI message and the TV is not handling this situation correctly.

For any player it is just a strange or at least unusual 720x288p file.

Yeah, the resolution is more suited for a mobile phone than for a TV. No wonder, that nobody tests this...

[Sergey]

For any player it is just a strange or at least unusual 720x288p file.

Yeah, the resolution is more suited for a mobile phone than for a TV. No wonder, that nobody tests this...

Problem exist not only on 576i, but also on 1080i H.265 channels. And in my case 90% of HEVC encoded channels have 1080i resolution.

[HansF]

Yeah, the resolution is more suited for a mobile phone than for a TV. No wonder, that nobody tests this...

Herrlich.

[Rudi16]

Problem exist not only on 576i, but also on 1080i H.265 channels.

And those also don't specify any "Scan type" (i.e. neither interlaced nor progressive)? If so, then we have a pretty strong evidence where the problem may lie.

BTW, are the preview images of the 1080i recordings also corrupted?

[Sergey]

In the attachment DR+ video of 1080i H.265 channel.
I am not sure, but I think there is no any "Scan type" too. Better ask @nerdlicht about it, as he found this.

Yes, preview of 1080i H.265 also corrupted. See below.

[nerdlicht]

Same with the 1080i file:

Bildschirmfoto 2018-08-21 um 12.03.43.png

This time even VLC wasn't able to play the file. Only the sound was playing, no picture. On the other hand, the Loewe was still able to play the video, although with the known 50% interlace issue.

These parameters make only sense, if you want to save massive bandwidth for cheaper broadcasting or for mobile devices, as @Rudi16 already mentioned.
Just a few numbers: the 576i file includes 720 x 288 = 207.360 pixels (and alternating by one line 50 times a second). The task for your Loewe is now to look brilliant on his UHD display with 8.294.400 pixels. Quit a difference and not that easy with these creepy files, if you ask me...

[Sergey]

This time even VLC wasn't able to play the file. Only the sound was playing, no picture.

It is strange, my VLC player able to play this file. But it is old version of VLC - v.2.2.1.

These parameters make only sense, if you want to save massive bandwidth for cheaper broadcasting...

Yes, I think so too.
I have sent question about video stream parameters to my satellite TV provider. Waiting for answer.

[Sergey]

I received an answer from my SAT provider:

Encoding is 8-bit H.265 4:2:0, Main Profile, interlaced, 50 fps, width and height are 720x576 for SD and 1920x1080 for HD.

I received next comment from CCC:

As already discussed in the forum the signal attributes seem to differ from standard attributes of DVB-signals. As we have some stages with motion interpolation and de-interlacer I want to recommend to play them without electronic helpers: Menü pictures: "film quality improvement" - set to off, image+ off, DNC off, Deblocking filter off.
Use also the other way around - try to activate the stages step by step to see any difference.

I have set all stages to OFF, but it doesn't helps.

And today SD 576i HEVC channels works more strange. Interlaced effect arised and disappeared every second. Look videos in attachment, which I have made using my video camera.
Any suggestions? Is it broadcasting issue or Loewe issue?

[DanielaE]

The broadcaster is supposed to set the correct stream metadata up front. I'm not aware of any TV set which googles or emails for the actual stream parameters before starting to receive a TV stream.

[Sergey]

@DanielaE,
I don't understand what you mean?
There is international standard Recommendation ITU-T H.265. All TV sets must accept stream parameters using this standard. Why TV needs to googles?

[Rudi16]

It's getting interresting: This link shows how interlaced video should be encoded. When analyzing the DR+ recording '00000052' we find:

general_progressive_source_flag = 0 ---> O.K.
general_interlaced_source_flag = 1 ---> O.K.
general_frame_only_constraint_flag = 0 ---> O.K.
field_seq_flag = 1 ---> O.K.
frame_field_info_present_flag = 1 ---> O.K.

However, when the last two flags are on, picture timing SEIs (as specified in ITU-T H.265, section D.2.3) shall be present for each picture. But I can't find any of them! That's probably the reason why VLC, MPlayer and FFmpeg treat this file as progressive, which in fact causes the utterly wrong aspect ratio (the picture should be twice as high). So I'd say this video stream is not encoded correctly.

[Sergey]

It's really getting more and more interesting, because I already saw this link and have read ITU-T H.265, section D.2.3 a week ago
But I don't know how to extract SEI messages from the stream. So, thank you @Rudi16 for this information.

What will be really difficult, is to put this information to my SAT provider because its very big company and it seems, like they not want to hear me.

[nerdlicht]

However, when the last two flags are on, picture timing SEIs (as specified in ITU-T H.265, section D.2.3) shall be present for each picture.

Meine Rede und da diese Information nun mal fehlt:

Bildschirmfoto 2018-08-28 um 22.10.51.png

..., weiß der Loewe nicht welches Halbbild zuerst dargestellt werden soll.

Aber wir drehen uns im Kreis...

[Sergey]

Its unbeleivable, but I received a full answer from my SAT provider.
H.265 interlaced encoding is made according Fraunhofer Heinrich Hertz Institute, which located in GERMANY!!!
So, I need to repeat - it is Loewe software problem!

my SAT provider use next settings:
source_scan_type = 0
pic_struct=11 (Top field paired with next bottom field in output order) - according ITU-T H.265 Section D.3.3 Table D.2

Additional information in my next message.

[Sergey]

Additional information about interlaced encoding H.265 576i channel in attachments.

And SAT provider say, that Loewe TV possibly not handle SEI messages: field_seq_flag, frame_field_info_present_flag.

[Rudi16]

Using a different parser tool, I can now see the missing picture timing SEIs. So my statement here was incorrect. However, I noticed something different: pic_struct is not fixed at 11. It changes to 10 and back to 11 somewhere in the middle. The means, that top and bottom fields are changing their order. If the TV does not take this into account, it would perfectly explain what can be seen on the picture in the first message of this thread. Just look at the 'O' in EUROSPORT and imagine every two adjacent lines swapped...

[Sergey]

I noticed something different: pic_struct is not fixed at 11. It changes to 10 and back to 11...

I didn't exactly correctly translate the message from my SAT provider.
My SAT provider say:

for example, for this field pic_struct=11 (3.png).

And as it seen in Fraunhofer Heinrich Hertz Institute recommendation, pic_struct must changes to 10 and back to 11 with every field of frame.

[Sergey]

I asked my SAT provider, why they do not use pic_struct=1 and pic_struct=2 and received next answer:

Values pic_struct=1 and pic_struct=2 for HEVC is not recommended by ETSI TS 101 154 directly. They do not carry information about the interconnectedness of fields. It is a non-paired field syntax.
In case of any loss in the bitstream, which is quite common in DVBS, the decoder may not receive information about the parity of the field, which will lead to incorrect output to the screen (if you use the values 1 and 2)
pic_struct=1 Top field of frame
pic_struct=2 Botom field of frame

Against

pic_struct=11 top field paired with next bottom field in output order
pic_struct=10 bottom field paried with previous top field in output order

Excerpt from DVB standard ETSI TS 101 154 (5.14.1.6.1):

5.14.1.6.1 Picture Timing SEI Message
Encoding:
HEVC Bitstreams shall contain a picture timing SEI message for every access unit of a coded
video sequence and frame_field_info_present_flag shall be set to 1 in the VUI.
The value of pic_struct shall not be equal to 1 or 2.
NOTE 1:
Setting frame_field_info_present_flag to "1" indicates the presence of pic_struct to determine if the picture should be displayed as a frame or one or more fields. Possible values for pic_struct are defined in table D-2 of Recommendation ITU-T H.265 / ISO/IEC 23008-2:2013 [35]. The pic_struct values 1 and 2 are not allowed in bitstreams since these values do not carry field relationship information which may be needed by the IRD to avoid field parity loss in presence of transmission errors. This implies that nonpaired fields are to be avoided in HEVC Bitstreams, and that HEVC IRD may not be able to display correctly HEVC Bitstreams containing non-paired fields.
NOTE 2:
In the context of HEVC, paired fields are two fields that are in consecutive access units in decoding order as two coded fields of opposite parity of the same frame, regardless their display order.
Decoding:
HEVC IRDs shall support all values defined in pic_struct including all modes requiring field and frame repetition except pic_struct values 1 and 2. The HEVC IRDs need not make use of any other syntax elements (except pic_struct) in the picture timing SEI message, if these elements are present.

Question is - why Loewe TV doesn't conform Digital Video Broadcasting standard ETSI TS 101 154 and ITU-T H.265?
So, I am waiting for solution from Loewe.

[Sergey]

Loewe CCC asked me to provide 1 minute transport streams samples of HEVC 576i and 1080i channels.
I have made them using DR+.