During the testing for the DTS-HD MA/HRA passthrough issue, another issue got noticed which I’d like to address in this thread:
MPEG2 videos with NTSC resolution - 480p - and framerate - 29.970Hz - are causing massive stutter. They stutter in a regular, less-than-one-second interval. No frame drops are shown and the sound plays fine. The issue showed with some publicly available test files, so it’s easily reproducable for others with these files:
MediaInfo:
===================== General =====================
Complete name : [...]\dolby_aurora-DWEU.vob
Format : MPEG-PS
File size : 28.7 MB
Duration (ms) : 34s 17ms
Overall bit rate : 7 084 Kbps
===================== Video =====================
Id : 224 (0xE0)
Format : MPEG Video
Formatversion : Version 2
Formatprofile : Main@Main
Formatsettings, BVOP : Yes
Formatsettings, Matrix : Custom
Formatsettings, GOP : M=3, N=12
Duration (ms) : 34s 17ms
Bit rate : 6 500 Kbps
Width : 720 pixels
Height : 480 pixels
Display aspect ratio : 16:9
Frame rate : 29.970 (30000/1001) fps
Standard : NTSC
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.628
Time code of first frame : 01:11:58:00
Time code source : Group of pictures header
GOP, Open/Closed : Open
GOP, Open/Closed of first f : Closed
Stream size : 26.3 MB (92%)
===================== Audio =====================
Id : 189 (0xBD)-128 (0x80)
Format : AC-3
Format info : Audio Coding 3
Mode extension : CM (complete main)
Formatsettings, Endianness : Big
Muxing mode : DVD-Video
Duration (ms) : 33s 856ms
Bit rate mode : Constant
Bit rate : 448 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 KHz
Frame rate : 31.250 fps (1536 spf)
Compression mode : Lossy
Stream size : 1.81 MB (6%)
===================== Menu =====================
MediaInfo:
===================== General =====================
Complete name : [...]\dolby_rain-DWEU.vob
Format : MPEG-PS
File size : 30.4 MB
Duration (ms) : 36s 19ms
Overall bit rate : 7 069 Kbps
===================== Video =====================
Id : 224 (0xE0)
Format : MPEG Video
Formatversion : Version 2
Formatprofile : Main@Main
Formatsettings, BVOP : Yes
Formatsettings, Matrix : Custom
Formatsettings, GOP : M=3, N=12
Formatsettings, picture str : Frame
Duration (ms) : 36s 19ms
Bit rate : 6 500 Kbps
Width : 720 pixels
Height : 480 pixels
Display aspect ratio : 16:9
Frame rate : 29.970 (30000/1001) fps
Standard : NTSC
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Interlaced
Scan order : Top Field First
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.628
Time code of first frame : 01:08:58:00
Time code source : Group of pictures header
GOP, Open/Closed : Open
GOP, Open/Closed of first f : Closed
Stream size : 27.8 MB (92%)
===================== Audio =====================
Id : 189 (0xBD)-128 (0x80)
Format : AC-3
Format info : Audio Coding 3
Mode extension : CM (complete main)
Formatsettings, Endianness : Big
Muxing mode : DVD-Video
Duration (ms) : 35s 840ms
Bit rate mode : Constant
Bit rate : 448 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 KHz
Frame rate : 31.250 fps (1536 spf)
Compression mode : Lossy
Stream size : 1.91 MB (6%)
===================== Menu =====================
MediaInfo:
===================== General =====================
Complete name : [...]\dts_sonic_landscape-DWEU.vob
Format : MPEG-PS
File size : 20.4 MB
Duration (ms) : 19s 52ms
Overall bit rate mode : Variable
Overall bit rate : 8 999 Kbps
===================== Video =====================
Id : 224 (0xE0)
Format : MPEG Video
Formatversion : Version 2
Formatprofile : Main@Main
Formatsettings, BVOP : Yes
Formatsettings, Matrix : Custom
Formatsettings, GOP : M=3, N=12
Duration (ms) : 19s 52ms
Bit rate mode : Variable
Bit rate : 7 310 Kbps
Maximum bit rate : 7 500 Kbps
Width : 720 pixels
Height : 480 pixels
Display aspect ratio : 16:9
Frame rate : 29.970 (30000/1001) fps
Standard : NTSC
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.706
Time code of first frame : 01:00:00:00
Time code source : Group of pictures header
GOP, Open/Closed : Closed
Stream size : 16.6 MB (81%)
===================== Audio =====================
Id : 189 (0xBD)-136 (0x88)
Format : DTS
Format info : Digital Theater Systems
Mode : 16
Formatsettings, Endianness : Big
Muxing mode : DVD-Video
Duration (ms) : 18s 848ms
Bit rate mode : Constant
Bit rate : 1 510 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 KHz
Frame rate : 93.750 fps (512 spf)
Bit depth : 20 bits
Compression mode : Lossy
Stream size : 3.39 MB (17%)
===================== Menu =====================
Here are logs with hardware acceleration enabled for MPEG2:
http://paste.osmc.tv/eqapudamec
Playback with hardware acceleration turned on produces stutter although Vero seems to go into the correct display mode (60p is shown - question would be, if its 59.940Hz or 60Hz).
and logs with hardware acceleration disabled for MPEG2:
http://paste.osmc.tv/imaqocosox
When hardware acceleration is disabled, the stutter isn't there for the first few seconds of playback (60p is the display mode chosen by the Vero again) and then the display mode switches to 24p (short black screen and display mode switch).
It’s not a critical issue that should be fixed as soon as possible, but it occurs with a video format which is pretty basic: MPEG2 used for NTSC DVDs. So, I guess, it would be nice, if this could be fixed.
As I can’t test for a while from tomorrow on, I’d like to invite especially @JimKnopf to help testing here, if needed, as he discovered the issue, too.
It occured in the test thread and I didn’t notice the special framerate features of the files… I don’t have any others here.
