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Jerky Play on MP4

Black Hole

May contain traces of nut
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?
 

MontysEvilTwin

Well-Known Member
How does the original file play on the HDR-FOX? If this is OK, check that the frame rate has not been changed in the copies.
 
OP
Black Hole

Black Hole

May contain traces of nut
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
Black Hole

Black Hole

May contain traces of nut
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
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.
 
OP
Black Hole

Black Hole

May contain traces of nut
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.
 
OP
Black Hole

Black Hole

May contain traces of nut
Nice idea, but no dice. The resulting .ts is 10MB larger (on 160MB), and plays just the same.
 
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