Jerky Play on MP4

Black Hole

May contain traces of nut
#1
I have some MP4s derived from a YouTube download, and they play absolutely fine in Splash Lite. VRD complained about not being able to find various time indexes in the file when I was splitting the big (4 hour) MP4 download into chapter files, even after "fast stream fix", but it still did the job.

What has me worried is that the HDR-FOX plays them jerkily. The sound track is fine, but the video looks like a Keystone Kops movie. My hypothesis is that the Humax player doesn't like the stream, the same as VRD didn't.

Anybody know what I can do to sort it out?
 
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Black Hole

Black Hole

May contain traces of nut
#3
You're right - the original file plays fine, so it must be something VRD has done to the clips when exporting them. And there I was thinking VRD represented the gold standard! What to do?

Here's the data for the original:
Code:
===================== General =====================
Complete name               : G:\Downloads\Original.mp4
Format                      : MPEG-4
Format profile              : Base Media / Version 2
Codec Id                    : mp42
File size                   : 3.93 GB
Duration (ms)               : 4h 5mn
OverallBitRate_Mode/String  : Variable
Total bitrate               : 2 285 Kbps
Encoded date                : UTC 2016-05-14 02:33:17
Tagged date                 : UTC 2016-05-14 02:33:17
gsst                        : 0
gstd                        : 14758696

===================== Video =====================
Id                          : 1
Format                      : AVC
Format info                 : Advanced Video Codec
Format profile              : Main@L3.1
Use of CABAC                : Yes
RefFrames                   : 3 frames
Codec Id                    : avc1
Codec info                  : Advanced Video Coding
Duration (ms)               : 4h 5mn
Bitrate                     : 2 156 Kbps
Width                       : 1 280 pixels
Height                      : 720 pixels
Aspect ratio                : 16:9
Framerate mode              : Constant
Framerate                   : 25.000 fps
Colorimetry                 : YUV
Colos space                 : 4:2:0
Bit depth                   : 8 bits
Scan type                   : Progressive
Bits/(Pixel*Frame)          : 0.094
Stream size                 : 3.70 GB (94%)
Title                       : ISO Media file produced by Google Inc.
Encoded date                : UTC 2016-05-14 02:33:17
Tagged date                 : UTC 2016-05-14 02:33:17
colour_primaries            : BT.709
transfer_characteristics    : BT.709
matrix_coefficients         : BT.709

===================== Audio =====================
Id                          : 2
Format                      : AAC
Format info                 : Advanced Audio Codec
Format profile              : LC
Codec Id                    : 40
Duration (ms)               : 4h 5mn
Source_Duration/String      : 4h 5mn
Bitrate mode                : Variable
Bitrate                     : 126 Kbps
Channel(s)                  : 2 channels
ChannelPositions            : Front: L R
Sampling rate               : 44.1 KHz
Compression_Mode/String     : Lossy
Stream size                 : 221 MB (5%)
Source_StreamSize/String    : 221 MB (5%)
Title                       : ISO Media file produced by Google Inc.
Encoded date                : UTC 2016-05-14 02:33:17
Tagged date                 : UTC 2016-05-14 02:33:17
...and one of the clips:
Code:
===================== General =====================
Complete name               : G:\Downloads\Clip8.mp4
Format                      : MPEG-4
Format profile              : Base Media
Codec Id                    : isom
File size                   : 166 MB
Duration (ms)               : 9mn 25s
Total bitrate               : 2 464 Kbps
Encoded application         : Lavf54.63.104

===================== Video =====================
Id                          : 1
Format                      : AVC
Format info                 : Advanced Video Codec
Format profile              : Main@L3.1
Use of CABAC                : Yes
RefFrames                   : 3 frames
Format settings - GOP       : M=1, N=15
Codec Id                    : avc1
Codec info                  : Advanced Video Coding
Duration (ms)               : 9mn 25s
Bitrate                     : 2 332 Kbps
Width                       : 1 280 pixels
Height                      : 720 pixels
Aspect ratio                : 16:9
Framerate mode              : Constant
Framerate                   : 25.000 fps
Colorimetry                 : YUV
Colos space                 : 4:2:0
Bit depth                   : 8 bits
Scan type                   : Progressive
Bits/(Pixel*Frame)          : 0.101
Stream size                 : 157 MB (95%)
colour_primaries            : BT.709
transfer_characteristics    : BT.709
matrix_coefficients         : BT.709

===================== Audio =====================
Id                          : 2
Format                      : AAC
Format info                 : Advanced Audio Codec
Format profile              : LC
Codec Id                    : 40
Duration (ms)               : 9mn 24s
Bitrate mode                : Constant
Bitrate                     : 126 Kbps
Channel(s)                  : 2 channels
ChannelPositions            : Front: L R
Sampling rate               : 44.1 KHz
Compression_Mode/String     : Lossy
Stream size                 : 8.46 MB (5%)
 
Last edited:
OP
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Black Hole

Black Hole

May contain traces of nut
#4
Does nobody have anything to offer on this? My preference is to cure the existing clips, having spent a lot of effort splitting the master video into 18 "chapters", preferably by some kind of stream-fixing process rather than re-encoding.

If it proves necessary, I can (but prefer not to) redo the splitting if the original file is sorted out so that VRD likes it, but VRD is the preference because of its no re-encode editing.

Update: I tried using VRD's "quick stream fix" process on a clip, but it didn't help.

Summary: the clips play fine in Splash Lite on a PC, but the HDR-FOX plays the video jerkily (although the audio is fine). I also notice that it doesn't respond to "stop" at all well!
 
Last edited:

MontysEvilTwin

Well-Known Member
#5
The only differences I can see between the original and the clips is a very slightly different video bitrate and the fact that the audio bitrate mode has changed from variable to constant. I am stumped.
 
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Black Hole

Black Hole

May contain traces of nut
#6
I did a short clip to upload to Dropbox as an example (just a couple of minutes worth, 40MB), but it doesn't show the problem! I'm stumped.
 
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