mythplayer picks the wrong fps for 1080i matroska, degrading to 1xHW deint

[angela.schmid@…]

mythplayer chooses to use the avg_fps (50) instead of the codec_fps (25) for 1080i matroska movies, therefor mythplayer decides to degrade deinterlacing to max 1xHW.

The problem is most clearly with a movie with extreme horizontal panning. I have a movie which I want to archive in mkv (lossless_cut) with a view on a large Chinese dragon wall.

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L4.0
Format settings, CABAC                   : Yes
Format settings, ReFrames                : 4 frames
Format settings, GOP                     : M=4, N=28
Codec ID                                 : V_MPEG4/ISO/AVC
Bit rate                                 : 2 884 Kbps
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Variable
Original frame rate                      : 25.000 fps
Standard                                 : Component
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Interlaced
Scan order                               : Bottom Field First

CoreContext avformatdecoder.cpp:1247 (normalized_fps) - AFD: Selected FPS is 50 (avg 50 codec 25 container 1000 estimated 50)

Setting primary deinterlacing option (2xHW):

CoreContext videodisplayprofile.cpp:354 (GetFilteredDeint) - VDP: GetFilteredDeint() : vdpau -> 'vdpaubasicdoublerate'

Degrade to fallback deinterlacing option (max 1xHW):

CoreContext mythplayer.cpp:2384 (VideoStart) - Player(0): Video sync method can't support double framerate (refresh rate too low for 2x deint)
CoreContext videodisplayprofile.cpp:354 (GetFilteredDeint) - VDP: GetFilteredDeint(vdpauadvanced) : vdpau -> 'vdpauadvanced'

Mythplayer should use the codec_fps, which is correct for 1080i.

The following dirty patch fixes the problem:

diff --git a/mythtv/libs/libmythtv/avformatdecoder.cpp b/mythtv/libs/libmythtv/avformatdecoder.cpp
index 3a42b40..6698484 100644
--- a/mythtv/libs/libmythtv/avformatdecoder.cpp
+++ b/mythtv/libs/libmythtv/avformatdecoder.cpp
@@ -1221,7 +1221,11 @@ float AvFormatDecoder::normalized_fps(AVStream *stream, AVCodecContext *enc)

     // matroska demuxer sets the default_duration to avg_frame_rate
     // mov,mp4,m4a,3gp,3g2,mj2 demuxer sets avg_frame_rate
-    if ((QString(ic->iformat->name).contains("matroska") ||
+    if ((QString(ic->iformat->name).contains("matroska")) &&
+        container_fps < 121.0f && container_fps > 3.0f)
+        fps = container_fps;
+    else
+    if ((QString(ic->iformat->name).contains("xmatroska") ||
         QString(ic->iformat->name).contains("mov")) &&
         avg_fps < 121.0f && avg_fps > 3.0f)
         fps = avg_fps;

[Karl Egly]

Good catch, but can't we simply use av_guess_frame_rate which handles interlaced content, too? Either way, the attached patch should handle both progressive and interlaced content. Does it fix your issue?

[angela.schmid@…]

Patch didn't compile on 0.27 and master:

avformatdecoder.cpp: In member function ‘float AvFormatDecoder::normalized_fps(AVStream*, AVCodecContext*)’:
avformatdecoder.cpp:1351:13: error: ‘st’ was not declared in this scope

Changed 'st' to 'stream' and tested on 0.27-fixes.

The patch works for media as the one shown above.

I didn't had good luck with lossless_cut (uses mkvmerge) and 1080i material with minimal glitches, so I changed my workflow in the meantime and use ts-doctor (which at the end produces correct total times and proper FFWD) and avconv.

I don't have the original chinese wall recording anymore and the resulting mkv has been converted with the following:

avconv -y -i input-tsdoctor.mpg -r 25 -c:v libx264  -flags +ilme+ildct+loop -cmp chroma -deblock 0:0 -r 25 -bt 256k -coder 0 -me_method full -me_range 16 -subq 5 -partitions +parti4x4+parti8x8+partp8x -g 250 -keyint_min 25 -trellis 2 -sc_threshold 40 -i_qfactor 0.71 -b_strategy 1 -qcomp 0.6 -qdiff 4 -refs 2 -direct-pred 1 -wpredp 2 -rc_lookahead 30 -profile:v baseline -level 30 -bf 0 -coder 0 -crf 22 -qmin 2 -qmax 30 -b:v 5000K -c:a copy -ar 44100 -ac 2 -b:a 128K -map 0:0 -map 0:a:0 -sn -f matroska output.mkv

which produces MBAFF

General
Unique ID                                : 63265251044264927949292968836987650338 (0x2F9871B35334230A54E4639435FC8122)
Complete name                            : Die sieben Wunder Chinas S01E06 Die Verbotene Stadt.mkv
Format                                   : Matroska
Format version                           : Version 2
File size                                : 1.69 GiB
Duration                                 : 23mn 59s
Overall bit rate                         : 10.1 Mbps
Writing application                      : Lavf53.21.1
Writing library                          : Lavf53.21.1

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : Main@L3.0
Format settings, CABAC                   : No
Format settings, ReFrames                : 2 frames
Codec ID                                 : V_MPEG4/ISO/AVC
Duration                                 : 23mn 59s
Bit rate                                 : 9 489 Kbps
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 25.000 fps
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : MBAFF
Bits/(Pixel*Frame)                       : 0.183
Stream size                              : 1.59 GiB (94%)
Writing library                          : x264 core 120 r2151 a3f4407
Encoding settings                        : cabac=0 / ref=2 / deblock=1:0:0 / analyse=0x1:0x1 / me=umh / subme=5 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=2 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=0 / threads=12 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=tff / bluray_compat=0 / constrained_intra=0 / bframes=0 / weightp=0 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=30 / rc=crf / mbtree=1 / crf=22.0 / qcomp=0.60 / qpmin=2 / qpmax=30 / qpstep=4 / ip_ratio=1.41 / aq=1:1.00
Default                                  : Yes
Forced                                   : No

Your patch produces for MBAFF media the wrong FPS, interlacing is detected correctly:

CoreContext avformatdecoder.cpp:1256 (normalized_fps) - AFD: Selected FPS is 12.5 (avg 12.5 codec 25 container 1000 estimated 25 ticks_per_frame 2)
CoreContext mythplayer.cpp:1748 (SetFrameInterval) - Player(6): SetFrameInterval ps:1 scan:3
CoreContext mythplayer.cpp:670 (detectInterlace) - Player(6): detectInterlace(Detect Scan, Interlaced Scan, 12.5, 1080) ->Interlaced Scan

For MBAFF no patch is needed, my patch does not interfere.

OT: I searched for other tools other than mediainfo to inspect the interlace status, but couldn't find one showing interlacing for MBAFF media, any suggestions.

OT: Is MBAFF good, or should I use another avconv command, any suggestions.

[Karl Egly]

Thanks for testing. Sorry, I noticed the copy'n'paste error only after uploading the patch but forgot to upload the fixed patch :/ A quick search for MBAFF (mixed progressive and interlaced in within a frame) and ticks_per_frame leads to suggestion of "do not encode to interlaced unless your display really is interlaced" hints, see ​http://mewiki.project357.com/wiki/X264_Settings#tff OT: As you are reencoding the video you might as well deinterlace before encoding. Lets try with ffmpeg's own new helper function in the new patch. (this time its compile tested)

[angela.schmid@…]

All 1080i movies play correct, although I cannot tell the deinterlacing qualities as the best example I have is the chinese wall movie which I only have in MBAFF, which .

CoreContext avformatdecoder.cpp:1291 (normalized_fps) - AFD: Selected FPS is 25 (guess 25 avg 25 codec 25 container 1000 estimated 25)
CoreContext mythplayer.cpp:1748 (SetFrameInterval) - Player(0): SetFrameInterval ps:1 scan:3
CoreContext mythplayer.cpp:670 (detectInterlace) - Player(0): detectInterlace(Detect Scan, Interlaced Scan, 25, 1080) ->Interlaced Scan

However, I noticed converted with lossless_cut workflow media, plays correct, but deinterlacing is degraded and the debug information shows "misleading" data:

Unique ID                                : 215050711015139973841239614612672134380 (0xA1C942A8F50B9E98D99CE20C4FF4BCEC)
Complete name                            : lossless_cut.mkv
Format                                   : Matroska
Format version                           : Version 4 / Version 2
File size                                : 2.16 GiB
Duration                                 : 44mn 54s
Overall bit rate                         : 6 879 Kbps
Encoded date                             : UTC 2014-04-27 09:49:24
Writing application                      : mkvmerge v6.9.1 ('Blue Panther') 64bit built on Apr 18 2014 17:43:56
Writing library                          : libebml v1.3.0 + libmatroska v1.4.1

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L4.0
Format settings, CABAC                   : Yes
Format settings, ReFrames                : 3 frames
Codec ID                                 : V_MPEG4/ISO/AVC
Bit rate                                 : 6 358 Kbps
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Variable
Original frame rate                      : 25.000 fps
Standard                                 : Component
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Interlaced
Scan order                               : Top Field First
Default                                  : Yes
Forced                                   : No
Color primaries                          : BT.709
Transfer characteristics                 : BT.709
Matrix coefficients                      : BT.709

CoreContext avformatdecoder.cpp:1291 (normalized_fps) - AFD: Selected FPS is 50 (guess 50 avg 50 codec 25 container 1000 estimated 50)
CoreContext mythplayer.cpp:1748 (SetFrameInterval) - Player(1): SetFrameInterval ps:1 scan:3
CoreContext mythplayer.cpp:670 (detectInterlace) - Player(1): detectInterlace(Detect Scan, Interlaced Scan, 50, 1080) ->Progressive Scan
...
CoreContext mythplayer.cpp:3907 (ClearAfterSeek) - Player(7): ClearAfterSeek(0)
CoreContext mythxdisplay.cpp:201 (GetRefreshRate) - Doubling refresh rate for interlaced display.
CoreContext videodisplayprofile.cpp:354 (GetFilteredDeint) - VDP: GetFilteredDeint() : vdpau -> 'vdpaubasicdoublerate'
CoreContext videoout_vdpau.cpp:350 (SetupDeinterlace) - VidOutVDPAU: Enabled deinterlacing.
CoreContext vsync.cpp:265 (TryInit) - VSYNC: DRMVideoSync: Could not open device /dev/dri/card0, No such file or directory
CoreContext mythplayer.cpp:2384 (VideoStart) - Player(7): Video sync method can't support double framerate (refresh rate too low for 2x deint)
CoreContext videodisplayprofile.cpp:354 (GetFilteredDeint) - VDP: GetFilteredDeint(vdpauadvanced) : vdpau -> 'vdpauadvanced'
CoreContext videoout_vdpau.cpp:350 (SetupDeinterlace) - VidOutVDPAU: Enabled deinterlacing.
CoreContext mythxdisplay.cpp:201 (GetRefreshRate) - Doubling refresh rate for interlaced display.
CoreContext mythplayer.cpp:1780 (InitAVSync) - Player(7): Video timing method: RTC
CoreContext mythplayer.cpp:1784 (InitAVSync) - Player(7): Display Refresh Rate: 60.053 Video Frame Rate: 50.000

Never saw two different fps values. Deinterlacing is correctly detected during playback.

In playback debug: Video:1920x1080@50fps, FPS: 25.00fps
In Video Scan: detect(I)

OT: Thanks for the links: ​https://trac.bunkus.org/wiki/FAQ:WrongFrameRateDisplayed: which explains the mkv behaviour and the mediainfo peculiarities, but also does not suggest other tools.

​http://mewiki.project357.com/wiki/X264_Settings#tff I have a 1080i display. Deinterlacing to 1080p or 720p didn't give me good results. Using vdpau 2xdeinterlacing is the best. Thats the reason I detected the deinterlacing degradation for mkv.

[angela.schmid@…]

Hi Karl, I found a backup of the original Chinese wall recording (between 03:40-04:20). If you are interested please sent me a PM, I will make it available on my web server.

[angela.schmid@…]

Hello Karl, I see the issue is on info needed. I can not give you further infos. I can provide you with a test file as written above.

[Karl Egly]

Hi Angela, I did not understand if the patch fixed the issue without introducing a regression. Here's an updated version of the patch attachment:0001-use-av_guess_frame_rate-from-ffmpeg-2.2-to-replace-o.patch​

[angela.schmid@…]

Hi Karl, no, the patch does not fix the issue, when the mkv contains scan type interlaced. I have a file converted with avconv, which works, scan type MBAFF. A file converted with lossless_cut does not work, scan type interlaced.

I rerun the test with both files before and after the 0001-divide-framerate-by-number-of-ticks-fields-per-frame.patch on 0.27.1

The documented log files are attached below. I can provide the original ts and the two converted mkv files on my web server, please PM.

[angela.schmid@…]

Works in 0.28-fixes correct:

CoreContext avformatdecoder.cpp:1456 (normalized_fps) - AFD: Selected FPS is 25 (avg 25 codec 25 container 1000 estimated 25)
CoreContext mythplayer.cpp:685 (detectInterlace) - Player(0): detectInterlace(Detect Scan, Interlaced Scan, 25, 1080) ->Interlaced Scan
CoreContext videodisplayprofile.cpp:354 (GetFilteredDeint) - VDP: GetFilteredDeint() : vdpau -> 'vdpaubasicdoublerate'

In playback debug: Video:1920x1080@25fps, FPS: 25.00fps

In Video Scan: detect(I)

2xHW Deinterlace

Issue can be closed.

[Karl Egly]

thank you for reporting back