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shorn

macrumors regular
Original poster
Jun 29, 2010
206
16
Hi all,

Came across a problem today. I'm in the process of converting (from MKV to m4v with MKVTools) some 720p TV shows, started a new season, and for some reason the resulting m4v file is not playing back correctly.

The m4v file that I end up with plays in quicktime/iTunes, however I can only hear the audio, there is no video, just a black screen/image.

If I play said file in VLC, it plays back correctly. The original 720p MKV plays fine with Perian as well.

I had a look at the file with MediaInfo; heres the one that doesn't work:

PHP:
General / Container Stream #1
	Total Video Streams for this File.................1
	Total Audio Streams for this File.................2
	Video Codecs Used.................................AVC
	Audio Codecs Used.................................AC3 / AAC LC
	File Format.......................................MPEG-4
	Play Time.........................................20mn 50s
	Total File Size...................................675 MiB
	Total Stream BitRate..............................4 530 Kbps
Video Stream #1
	Codec (Human Name)................................AVC
	Codec (FourCC)....................................avc1
	Codec Profile.....................................High@L3.1
	Frame Width.......................................1 280 pixels
	Frame Height......................................720 pixels
	Frame Rate........................................23.976 fps
	Total Frames......................................29971
	Display Aspect Ratio..............................16:9
	Scan Type.........................................Progressive
	Color Space.......................................YUV
	Codec Settings (Summary)..........................2 Ref Frames
	QF (like Gordian Knot)............................0.180
	Codec Settings (CABAC)............................No
	Codec Settings (Reference Frames).................2
	Video Stream Length...............................20mn 50s 42ms
	Video Stream BitRate..............................3 986 Kbps
	Video Stream BitRate Mode.........................VBR
	Bit Depth.........................................8 bits
	Video Stream Size.................................594 MiB (88%)
	Date of Original Encoding.........................UTC 2011-01-20 12:55:09
	Color Primaries...................................BT.709-5, BT.1361, IEC 61966-2-4, SMPTE RP177
	Transfer Characteristics..........................BT.709-5, BT.1361
	Matrix Coefficients...............................BT.709-5, BT.1361, IEC 61966-2-4 709, SMPTE RP177
Audio Stream #1
	Codec.............................................AC-3
	Codec (FourCC)....................................ac-3
	Audio Stream Length...............................20mn 50s 16ms
	Audio Stream BitRate..............................384 Kbps
	Audio Stream BitRate Mode.........................CBR
	Number of Audio Channels..........................6
	Audio Channel's Positions.........................Front: L C R, Side: L R, LFE
	Sampling Rate.....................................48.0 KHz
	Bit Depth.........................................16 bits
	Audio Stream Size.................................57.2 MiB (8%)
	Audio Stream Language.............................English
	Date of Original Encoding.........................UTC 2011-01-20 12:55:07
Audio Stream #2
	Codec.............................................AAC
	Codec (FourCC)....................................40
	Audio Stream Length...............................20mn 49s 962ms
	Audio Stream BitRate..............................156 Kbps
	Audio Stream BitRate Mode.........................VBR
	Number of Audio Channels..........................2
	Audio Channel's Positions.........................Front: L R
	Sampling Rate.....................................48.0 KHz
	Audio Stream Size.................................23.2 MiB (3%)
	Audio Stream Language.............................English
	Date of Original Encoding.........................UTC 2011-01-20 12:56:04

And heres one that plays fine:

PHP:
General / Container Stream #1
	Total Video Streams for this File.................1
	Total Audio Streams for this File.................1
	Video Codecs Used.................................AVC
	Audio Codecs Used.................................AAC LC
	File Format.......................................MPEG-4
	Play Time.........................................23mn 2s
	Total File Size...................................721 MiB
	Total Stream BitRate..............................4 377 Kbps
	Title (Tag).......................................Pilot
	Encoded with......................................iFlicks
Video Stream #1
	Codec (Human Name)................................AVC
	Codec (FourCC)....................................avc1
	Codec Profile.....................................High@L3.1
	Frame Width.......................................1 280 pixels
	Frame Height......................................720 pixels
	Frame Rate........................................23.976 fps
	Total Frames......................................33145
	Display Aspect Ratio..............................16:9
	Scan Type.........................................Progressive
	Color Space.......................................YUV
	Codec Settings (Summary)..........................2 Ref Frames
	QF (like Gordian Knot)............................0.191
	Codec Settings (CABAC)............................No
	Codec Settings (Reference Frames).................2
	Video Stream Length...............................23mn 2s 422ms
	Video Stream BitRate..............................4 211 Kbps
	Video Stream BitRate Mode.........................VBR
	Bit Depth.........................................8 bits
	Video Stream Size.................................694 MiB (96%)
	Date of Original Encoding.........................UTC 2011-01-12 19:12:59
	Color Primaries...................................BT.709-5, BT.1361, IEC 61966-2-4, SMPTE RP177
	Transfer Characteristics..........................BT.709-5, BT.1361
	Matrix Coefficients...............................BT.709-5, BT.1361, IEC 61966-2-4 709, SMPTE RP177
Audio Stream #1
	Codec.............................................AAC
	Codec (FourCC)....................................40
	Audio Stream Length...............................23mn 2s 442ms
	Audio Stream BitRate..............................154 Kbps
	Audio Stream BitRate Mode.........................VBR
	Number of Audio Channels..........................2
	Audio Channel's Positions.........................Front: L R
	Sampling Rate.....................................48.0 KHz
	Audio Stream Size.................................25.4 MiB (4%)
	Audio Stream Language.............................English
	Date of Original Encoding.........................UTC 2011-01-12 19:12:57


Any ideas?
 
The working one has an even higher bitrate than the non-working one, so I'm not sure that that's the issue.
 
Both of these files have been run through MKVTools, with no encoding, video is passed through. Its really weird! Specs wise they seem pretty much the same!
 
Sometimes the passthrough option just won't work.
The creator of mkvtools has stated so. Try the pass-1 encoding and it should be fine
 
I'm no expert here, but I know that MKVTools can only passthrough mkv files encoded in h.264. It's possible that your source file isn't (even though it's in a mkv container), which is why you're getting no video output. If that's the case, you'll have to re-encode the file, either with MKVTools or Handbrake.
 
OK, well to further complicate the issue!
The vid is definitely h.264.

I now have this playing in iTunes and on the AppleTV. However this is by repacking into an mp4 container, with just AC3 audio. When I deselected the "Add 2 CH track" it seemed to work. Obviously this will not play on the iPhone/iPad, but my main purpose was for the ATV anyhow.
 
Ive been having the same problem with a 720p MKV I want to stream to my xbox.

I've been trying to re-encode it to a M4V as an h.264 passthrough, but encoding the audio as a 2.0 aac (xbox wont support a 5.1 aac audio encode).

The encode completes, but the video wont play....

I've been trying to use videomonkey to do it...

any help would be highly appreciated.
 
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