Mailing List Archive

#12993: HEVC/H265 Parser missed for Recordings
----------------------------------+-------------------------
Reporter: laasa@… | Owner:
Type: Bug Report - General | Status: new
Priority: minor | Milestone: unknown
Component: MythTV - General | Version: 0.28.1
Severity: low | Resolution:
Keywords: HEVC,H.265,H265 | Ticket locked: 0
----------------------------------+-------------------------

Comment (by laasa@…):

Another result of the missing parser is that the forward / rewind is not
working or not working correct when playing the recordings. It looks like
that MARK_TOTAL_FRAMES is not set correct in recordedmarkup table.

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Ticket URL: <https://code.mythtv.org/trac/ticket/12993#comment:1>
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#12993: HEVC/H265 Parser missed for Recordings
----------------------------------+-------------------------
Reporter: laasa@… | Owner:
Type: Bug Report - General | Status: new
Priority: minor | Milestone: unknown
Component: MythTV - General | Version: 0.28.1
Severity: low | Resolution:
Keywords: HEVC,H.265,H265 | Ticket locked: 0
----------------------------------+-------------------------

Comment (by bjoernv@…):

I also found, that forward / rewind does not work precisely for HEVC/H265
recordings. Also, if the timeline already shows, that the recording is
finished, it may play some minutes longer.

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Ticket URL: <https://code.mythtv.org/trac/ticket/12993#comment:2>
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#12993: HEVC/H265 Parser missed for Recordings
----------------------------------+-------------------------
Reporter: laasa@… | Owner:
Type: Bug Report - General | Status: new
Priority: minor | Milestone: unknown
Component: MythTV - General | Version: 0.28.1
Severity: low | Resolution:
Keywords: HEVC,H.265,H265 | Ticket locked: 0
----------------------------------+-------------------------

Comment (by bjoernv@…):

Instead of writing a new HEVCParser (a HEVC/H.265 variant of the existing
mythtv/libs/libmythtv/mpeg/H264Parser.cpp parser) from scratch, it may be
a good idea to base on the existing FFmpeg parsers.

Newer versions of FFmpeg including FFmpeg 3.2 included in MythTV 29, have
a parser called h2645_parse
(mythtv-29/mythtv/external/FFmpeg/libavcodec/h2645_parse.c). The HEVC code
(mythtv-29/mythtv/external/FFmpeg/libavcodec/hevc_parse.c) is small,
because most functions are inherited from h2645_parse.

I can not estimate, how much work this will be.

Since none of the VDR systems for Linux currently have full support for
the German DVB-T2 HD (HEVC codec) TV standard, some people work on hacks,
which work more or less. Here people from Linux DVR have made patches for
HEVC:

[RFC] H.265 Frame-Parser
https://www.vdr-portal.de/forum/index.php?thread/128740-rfc-h-265-frame-
parser/
(in German)

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Ticket URL: <https://code.mythtv.org/trac/ticket/12993#comment:3>
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#12993: HEVC/H265 Parser missed for Recordings
----------------------------------+-------------------------
Reporter: laasa@… | Owner:
Type: Bug Report - General | Status: new
Priority: minor | Milestone: unknown
Component: MythTV - General | Version: 0.28.1
Severity: low | Resolution:
Keywords: HEVC,H.265,H265 | Ticket locked: 0
----------------------------------+-------------------------

Comment (by bjoernv@…):

Yesterday I recorded 90 minutes movie (German DVB T2 HD HEVC). I wanted to
stop watching at 60 minutes and tried to set a bookmark. Unfortunately
MythTV miscalculated the movie length (around 60 minutes), so that it was
not possible to set the bookmark. Today MythTV frontend shows a video
length of 1:26:46 (around 86 minutes). The video length calculation is
very unreliable for HEVC.

--
Ticket URL: <https://code.mythtv.org/trac/ticket/12993#comment:4>
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#12993: HEVC/H265 Parser missed for Recordings
-------------------------------------+--------------------------
Reporter: laasa@… | Owner: pbennett
Type: Bug Report - General | Status: assigned
Priority: minor | Milestone: unknown
Component: MythTV - Video Playback | Version: 0.28.1
Severity: low | Resolution:
Keywords: HEVC,H.265,H265 | Ticket locked: 0
-------------------------------------+--------------------------
Changes (by pbennett):

* owner: => pbennett
* status: new => assigned
* component: MythTV - General => MythTV - Video Playback


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Ticket URL: <https://code.mythtv.org/trac/ticket/12993#comment:5>
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#12993: HEVC/H265 Parser missed for Recordings
-------------------------------------+--------------------------
Reporter: laasa@… | Owner: pbennett
Type: Bug Report - General | Status: assigned
Priority: minor | Milestone: unknown
Component: MythTV - Video Playback | Version: 0.28.1
Severity: low | Resolution:
Keywords: HEVC,H.265,H265 | Ticket locked: 0
-------------------------------------+--------------------------

Comment (by pbennett):

It looks like dtvrecorder it caters for H264 or MPEG2. Worse is that if
the stream is not H264 it is treated as MPEG2. So it appears your H265
broadcast is being treated like MPEG2.

If it creates a seektable based on wrong assumptions, seeking and
recording length will be affected. It may be better to have no seektable
at all. You could try deleting the seektable and see if that helps.

I would think the continuity detection would also be wrong. Is your
recording being flagged as failed?

The frame parser you mention only splits the packet into NAL units. We
need more information from the packet, in particular the location of key
frames.

I suspect the H264 parser may work for H265 better than the MPEG2 parser
works, since in the code examples the H265 parser seems to be based on the
H264 parser. I do not have access to any H265 broadcasts so I cannot test
this. Perhaps somebody could try it out.

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Ticket URL: <https://code.mythtv.org/trac/ticket/12993#comment:6>
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#12993: HEVC/H265 Parser missed for Recordings
-------------------------------------+--------------------------
Reporter: laasa@… | Owner: pbennett
Type: Bug Report - General | Status: assigned
Priority: minor | Milestone: unknown
Component: MythTV - Video Playback | Version: 0.28.1
Severity: low | Resolution:
Keywords: HEVC,H.265,H265 | Ticket locked: 0
-------------------------------------+--------------------------

Comment (by bjoernv@…):

Replying to [comment:6 pbennett]:
> If it creates a seektable based on wrong assumptions, seeking and
recording length will be affected. It may be better to have no seektable
at all. You could try deleting the seektable and see if that helps.

Could you give me a hint, how to delete the seektable for a specific
recording?

> I would think the continuity detection would also be wrong. Is your
recording being flagged as failed?

No.

> The frame parser you mention only splits the packet into NAL units. We
need more information from the packet, in particular the location of key
frames.
>
> I suspect the H264 parser may work for H265 better than the MPEG2 parser
works, since in the code examples the H265 parser seems to be based on the
H264 parser. I do not have access to any H265 broadcasts so I cannot test
this. Perhaps somebody could try it out.

Would it be helpful for you, if I upload a recorded sample to Google Drive
etc.?

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Ticket URL: <https://code.mythtv.org/trac/ticket/12993#comment:7>
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#12993: HEVC/H265 Parser missed for Recordings
-------------------------------------+--------------------------
Reporter: laasa@… | Owner: pbennett
Type: Bug Report - General | Status: assigned
Priority: minor | Milestone: unknown
Component: MythTV - Video Playback | Version: 0.28.1
Severity: low | Resolution:
Keywords: HEVC,H.265,H265 | Ticket locked: 0
-------------------------------------+--------------------------

Comment (by pbennett):

Clear the seektable this way
{{{
mythutil --clearseektable --chanid 2763 --starttime 20170814180000
}}}
To get the chanid and starttime you can look at the information (press I
in the watch recordings window). The file name will normally be something
like 2763_20170814180000.ts or 2763_20170814180000.mpg. In either case the
first 4 digits are the chanid and the rest is the start time.

To verify you can run this
{{{
mythutil --checkrecordings
}}}
That will tell you which recordings do not have seektables

The fix is really going to have to be in the recorder, so having an
already recorded file will not really help much. Let's see if deleting the
seektable helps, then maybe I can prevent it from creating a seektable for
H265 recordings, as an interim step.

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Ticket URL: <https://code.mythtv.org/trac/ticket/12993#comment:8>
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#12993: HEVC/H265 Parser missed for Recordings
-------------------------------------+--------------------------
Reporter: laasa@… | Owner: pbennett
Type: Bug Report - General | Status: assigned
Priority: minor | Milestone: unknown
Component: MythTV - Video Playback | Version: 0.28.1
Severity: low | Resolution:
Keywords: HEVC,H.265,H265 | Ticket locked: 0
-------------------------------------+--------------------------

Comment (by bjoernv@…):

Replying to [comment:8 pbennett]:
> Clear the seektable this way
> {{{
> mythutil --clearseektable --chanid 2763 --starttime 20170814180000
> }}}

Clearing the seektable seems to help. I recorded 6:13 minutes of a TV
video. I verified the video length with a video editor (Avidemux).
Mythfrontend showed me a video length of 5:41 minutes before clearing the
seektable. After I cleared the seektable, also Mythfrontend shows 6:13
minutes.

Fast forward and reverse seems to work better after clearing the
seektable. But fast forward and reverse does not jump to I-frames, so that
the user has to wait around 1 second until the display is clear.

--
Ticket URL: <https://code.mythtv.org/trac/ticket/12993#comment:9>
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#12993: HEVC/H265 Parser missed for Recordings
-------------------------------------+-------------------------------
Reporter: laasa@… | Owner: Peter Bennett
Type: Bug Report - General | Status: assigned
Priority: minor | Milestone: needs_triage
Component: MythTV - Video Playback | Version: 0.28.1
Severity: low | Resolution:
Keywords: HEVC,H.265,H265 | Ticket locked: 0
-------------------------------------+-------------------------------
Changes (by Stuart Auchterlonie):

* milestone: unknown => needs_triage


Comment:

Peter,

We have a parser now, is there something we need to add to fix this too?


Regards
Stuart

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Ticket URL: <https://code.mythtv.org/trac/ticket/12993#comment:11>
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#12993: HEVC/H265 Parser missed for Recordings
-------------------------------------+-------------------------------
Reporter: laasa@… | Owner: Peter Bennett
Type: Bug Report - General | Status: closed
Priority: minor | Milestone: needs_triage
Component: MythTV - Video Playback | Version: 0.28.1
Severity: low | Resolution: Fixed
Keywords: HEVC,H.265,H265 | Ticket locked: 0
-------------------------------------+-------------------------------
Changes (by Peter Bennett):

* status: assigned => closed
* resolution: => Fixed


Comment:

Fixed by John Poet in 7fc5e803134d8d429878ef062357ede8c73f1404

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Ticket URL: <https://code.mythtv.org/trac/ticket/12993#comment:12>
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#12993: HEVC/H265 Parser missed for Recordings
-------------------------------------+-------------------------------
Reporter: laasa@… | Owner: Peter Bennett
Type: Bug Report - General | Status: closed
Priority: minor | Milestone: 32.0
Component: MythTV - Video Playback | Version: 0.28.1
Severity: low | Resolution: Fixed
Keywords: HEVC,H.265,H265 | Ticket locked: 0
-------------------------------------+-------------------------------
Changes (by Stuart Auchterlonie):

* milestone: needs_triage => 32.0


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Ticket URL: <https://code.mythtv.org/trac/ticket/12993#comment:13>
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