user17716: I wanted to play UHD (4k) videos in my new LeTV (Super3 X55). 
So I used youtube-dl to download 4k YouTube videos (which are humongous btw) but for some reason most of them do not play.
The TV's website specifically states:

HEVC/H.265 hardware video decoding, up to 4K@60fps

But only a few files play. I'm thinking the issue is something to do with codecs or formats.
So I compared the info of files which did play with those that didn't. But I can't figure out the difference. Here are two files which played and two that didn't.

These two files played beautifully:
File 1 :: GoPro video
C:\Users\Hackathon\Videos\HD or 4k\GoPro\NA\NA - GoPro HERO4 - The Adventure of Life in 4K.mkv
   General
      Unique ID : 98713554682895442793938602234209693471 (0x4A438A01ACFC3EF5104AF4D6A778EF1F)
      Complete name : C:\Users\Hackathon\Videos\HD or 4k\GoPro\NA\NA - GoPro HERO4 - The Adventure of Life in 4K.mkv
      Format : Matroska
      Format version : Version 4 / Version 2
      File size : 581 MiB
      Duration : 4 min
      Overall bit rate mode : Variable
      Overall bit rate : 19.2 Mb/s
      Movie name : GoPro HERO4: The Adventure of Life in 4K
      Description : All around the world GoPro users are capturing incredible experiences, from the heart-stopping to the heartfelt. Into the caldron of an active volcano, the neon streets of Japan, a refuge for wild mustangs, scaling an iceberg, the world’s biggest dance party, or a whale rescue mission, GoPros have documented every moment. See how GoPro’s new line of our most advanced cameras ever allow you to beautifully and authentically capture and share the experiences that bring purpose, adventure, and joy to your life.

Shot 100% on the new GoPro HERO4 camera from http://GoPro.com.

The HERO4 features ultra high resolution quality of 4K at 30 frames per second + high frames rates at 1080p120. Incredible low light capabilities, including our new nightlapse setting. 2X the high fidelity sound. Faster processing. Protune settings that unlock manual control of many of your GoPro’s features, and so much more. Learn more and be inspired by the most advanced GoPro cameras yet: http://GoPro.com

It’s your life. BE A HERO.

MUSIC
"Run Boy Run" performed by Woodkid
Courtesy of Interscope Records under license from Universal Music Enterprises

FEATURED CHARACTERS

TOMORROWLAND (Boom, Belgium)
Erin Edenholm
Joanna Piotrowska
Steve Aoki
Krewella - Jahan Yousaf and Jasmine Yousaf
Dimitri Vegas
Like Mike

LAVA LAKE (Ambrym Island, Vanuatu)
Geoff Mackley
Brad Ambrose

ICEBERG CLIMB (Ilulissat, Greenland)
Klemen Premrl
Aljaz Anderle
Thierry Dubois

WILD MUSTANGS (Wells, Nevada)
Clay Nannini

JAPAN STREETS (Tokyo, Japan)
Akira Nakai
Shinichi Moroboshi
Nanami Tsukamoto

ORCA RESCUE (Whangarei, New Zealand)
Dr. Ingrid Visser
Terry Hardie
Dian and her two baby orca


SPECIAL THANKS
Tomorrowland (http://www.tomorrowland.com)
Michael Dujardin
Vanuatu Heli (http://www.vanuatuhelicopters.com)
Andy Martin
Black Diamond (http://www.blackdiamondequipment.com)
Madeline Pickens (http://mustangmonument.com) (http://savingamericasmustangs.org)
Orca Research Trust (http://orcaresearch.org)
Andy Casagrande (http://www.abc4explore.com/)
Steve Hathaway
Lily Kozman
      ARTIST : GoPro
      DATE : 20140929
      PURL : https://www.youtube.com/watch?v=wTcNtgA6gHs
   Video #1
      ID : 1
      Format : AVC
      Format/Info : Advanced Video Codec
      Format profile : High@L5.1
      Format settings, CABAC : No
      Format settings, ReFrames : 2 frames
      Codec ID : V_MPEG4/ISO/AVC
      Duration : 4 min
      Bit rate : 18.7 Mb/s
      Width : 3 840 pixels
      Height : 2 160 pixels
      Display aspect ratio : 16:9
      Frame rate mode : Constant
      Frame rate : 29.970 (30000/1001) FPS
      Color space : YUV
      Chroma subsampling : 4:2:0
      Bit depth : 8 bits
      Scan type : Progressive
      Bits/(Pixel*Frame) : 0.075
      Stream size : 566 MiB (97%)
      Default : Yes
      Forced : No
      Color range : Limited
      Color primaries : BT.709
      Transfer characteristics : BT.709
      Matrix coefficients : BT.709
      DURATION : 00:04:13.887000000
      HANDLER_NAME : VideoHandler
   Audio #2
      ID : 2
      Format : Vorbis
      Format settings, Floor : 1
      Codec ID : A_VORBIS
      Duration : 4 min
      Bit rate mode : Variable
      Bit rate : 128 kb/s
      Channel(s) : 2 channels
      Sampling rate : 44.1 kHz
      Compression mode : Lossy
      Stream size : 3.87 MiB (1%)
      Writing application : Google
      Language : English
      Default : Yes
      Forced : No
      DURATION : 00:04:13.906000000

File 2 :: Wonder Woman Trailer
C:\Users\Hackathon\Music\iTunes\iTunes Media\Automatically Add to iTunes\WONDER WOMAN Trailer #2 [2017] (Ultra-HD 4K).mp4
   General
      Complete name : C:\Users\Hackathon\Music\iTunes\iTunes Media\Automatically Add to iTunes\WONDER WOMAN Trailer #2 [2017] (Ultra-HD 4K).mp4
      Format : MPEG-4
      Format profile : Base Media
      Codec ID : isom (isom/iso2/avc1/mp41)
      File size : 222 MiB
      Duration : 2 min
      Overall bit rate : 11.5 Mb/s
      Movie name : WONDER WOMAN Trailer #2 [2017] (Ultra-HD 4K)
      Writing application : Lavf57.48.103
      Cover : Yes
   Video #1
      ID : 1
      Format : AVC
      Format/Info : Advanced Video Codec
      Format profile : High@L5.1
      Format settings, CABAC : Yes
      Format settings, ReFrames : 4 frames
      Codec ID : avc1
      Codec ID/Info : Advanced Video Coding
      Duration : 2 min
      Bit rate : 11.3 Mb/s
      Width : 3 840 pixels
      Height : 2 160 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 : Progressive
      Bits/(Pixel*Frame) : 0.055
      Stream size : 219 MiB (99%)
      Writing library : x264 core 148 r2705 3f5ed56
      Encoding settings : cabac=1 / ref=3 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=6 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=23.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
      Language : English
   Audio #2
      ID : 2
      Format : AAC
      Format/Info : Advanced Audio Codec
      Format profile : LC
      Codec ID : 40
      Duration : 2 min
      Bit rate mode : Constant
      Bit rate : 129 kb/s
      Channel(s) : 2 channels
      Channel positions : Front: L R
      Sampling rate : 48.0 kHz
      Frame rate : 46.875 FPS (1024 spf)
      Compression mode : Lossy
      Stream size : 2.49 MiB (1%)
      Language : English
      Default : Yes
      Alternate group : 1


These two files did NOT play:
"In A Nutshell" video:
C:\Users\Hackathon\Videos\HD or 4k\Kurzgesagt – In a Nutshell\NA\NA - A New History for Humanity – The Human Era.mkv
   General
      Unique ID : 151773273920022300678100154581510254877 (0x722E78240BE681AAC8163B7BB9E3F11D)
      Complete name : C:\Users\Hackathon\Videos\HD or 4k\Kurzgesagt – In a Nutshell\NA\NA - A New History for Humanity – The Human Era.mkv
      Format : Matroska
      Format version : Version 4 / Version 2
      File size : 130 MiB
      Duration : 7 min
      Overall bit rate : 2 306 kb/s
      Movie name : A New History for Humanity – The Human Era
      Description : It is time to reframe how we think about our past.
We need a new year 0 for humanity. But which one should we choose and why?



http://www.youtube.com/timedtext_cs_panel?c=UCsXVk37bltHxD1rDPwtNM8Q&amp;tab=2

A New History for Humanity – The Human Era
      Writing application : Lavf57.48.103
      Writing library : Lavf57.48.103 / Lavf57.48.103
      Comment : It is time to reframe how we think about our past.
We need a new year 0 for humanity. But which one should we choose and why?


THANKS A LOT TO OUR LOVELY PATRONS FOR SUPPORTING US:

Stuart Alldritt, Tasia Pele, Stan Serebryakov, Mike Janzen, Jason Heddle, August, Daniel Smith, Jonathan Herman, Rahul Rachuri, Piotr Gorzelany, Lisa Allcott, Горан Гулески, Eric Ziegast, Kean Drake, Friendly Stranger, NicoH, Adrian Rutkiewicz, Markus Klemm, Leandro Nascimento, Gary Chan, Shawhin Layeghi, Oscar Hernandez, Dale Prinsse, Vaclav Vyskocil, Sup3rW00t, Ryan Coonan, Tam Lerner, Dewi Cadat, Luis Aguirre, Andy McVey, Vexorum, Boris, Adam Wisniewski, Yannic Schreiber, Erik Lilly, Ellis, Dmitry Starostin, Akshay Joshi, Peter Tinti, kayle Clark, Mortimer Brewster, Marc Legault, Sumita Pal, Tarje Hellebust Jr., streetdragon95, Taratsamura, Sam Dickson, Bogdan Firicel, Saul Vera, Aaron Jacobs, Ben Arts, R B Dean, Kevin Beedon, Patrik Pärkinen, Duncan Graham, Johan Thomsen, Emily Tran, Adam Flanc, Adam Jermyn, Ali Uluyol

Help us caption & translate this video!

http://www.youtube.com/timedtext_cs_panel?c=UCsXVk37bltHxD1rDPwtNM8Q&amp;tab=2

A New History for Humanity – The Human Era
      ARTIST : Kurzgesagt – In a Nutshell
      DATE : 20161207
      PURL : https://www.youtube.com/watch?v=czgOWmtGVGs
   Video #1
      ID : 1
      Format : AVC
      Format/Info : Advanced Video Codec
      Format profile : High@L4.2
      Format settings, CABAC : Yes
      Format settings, ReFrames : 3 frames
      Codec ID : V_MPEG4/ISO/AVC
      Duration : 7 min
      Width : 1 920 pixels
      Height : 1 080 pixels
      Display aspect ratio : 16:9
      Frame rate mode : Constant
      Frame rate : 60.000 FPS
      Color space : YUV
      Chroma subsampling : 4:2:0
      Bit depth : 8 bits
      Scan type : Progressive
      Default : Yes
      Forced : No
      Color range : Limited
      Color primaries : BT.709
      Transfer characteristics : BT.709
      Matrix coefficients : BT.709
      DURATION : 00:07:52.447000000
      HANDLER_NAME : VideoHandler
   Audio #2
      ID : 2
      Format : Opus
      Codec ID : A_OPUS
      Duration : 7 min
      Channel(s) : 2 channels
      Channel positions : Front: L R
      Sampling rate : 48.0 kHz
      Compression mode : Lossy
      Delay relative to video : -14 ms
      Language : English
      Default : Yes
      Forced : No
      DURATION : 00:07:52.461000000

Finally a puppies video:
C:\Users\Hackathon\Videos\HD or 4k\Jacob   Katie Schwarz\NA\NA - PUPPIES BATH IN 4K (ULTRA HD).mkv
   General
      Unique ID : 172223577613529861860930485370882755628 (0x81910DF562C189096C7EE7D95D3A0C2C)
      Complete name : C:\Users\Hackathon\Videos\HD or 4k\Jacob   Katie Schwarz\NA\NA - PUPPIES BATH IN 4K (ULTRA HD).mkv
      Format : Matroska
      Format version : Version 4 / Version 2
      File size : 311 MiB
      Duration : 2 min
      Overall bit rate : 17.4 Mb/s
      Movie name : PUPPIES BATH IN 4K (ULTRA HD)
      Description : To view this video in 4K select "Original" in the resolution menu. If you're having trouble with 4K playback, try using different browsers, like Internet Explorer, Firefox or Google Chrome.

Our friends just had puppies and we took the chance to film them this last weekend before they all left for new homes.

This video was filmed and edited at 4K (4096x2304) resolution, four times greater than regular 1080p HD. All 4K file are available upon request. Shot on Red Epic.

Follow us on twitter: http://www.twitter.com/jakeschwarz


Tech spec:
Red Epic (M642) w/ Ti Canon Mount
16-35mm & 50mm L-Series Lens
Adobe Premiere CS6 and DaVinci Resolve

Question or business inquires:
contact@mysterybox.us

Copyright © 2014 Mystery Box, LLC. All Rights Reserved.
      Writing application : Lavf57.48.103
      Writing library : Lavf57.48.103 / Lavf57.48.103
      Comment : To view this video in 4K select "Original" in the resolution menu. If you're having trouble with 4K playback, try using different browsers, like Internet Explorer, Firefox or Google Chrome.

Our friends just had puppies and we took the chance to film them this last weekend before they all left for new homes.

This video was filmed and edited at 4K (4096x2304) resolution, four times greater than regular 1080p HD. All 4K file are available upon request. Shot on Red Epic.

Follow us on twitter: http://www.twitter.com/jakeschwarz


Tech spec:
Red Epic (M642) w/ Ti Canon Mount
16-35mm & 50mm L-Series Lens
Adobe Premiere CS6 and DaVinci Resolve

Question or business inquires:
contact@mysterybox.us

Copyright © 2014 Mystery Box, LLC. All Rights Reserved.
      ARTIST : Jacob   Katie Schwarz
      DATE : 20120922
      PURL : https://www.youtube.com/watch?v=SMwxZO2UjBw
   Video #1
      ID : 1
      Format : AVC
      Format/Info : Advanced Video Codec
      Format profile : High@L5.1
      Format settings, CABAC : No
      Format settings, ReFrames : 2 frames
      Codec ID : V_MPEG4/ISO/AVC
      Duration : 2 min
      Width : 4 096 pixels
      Height : 2 304 pixels
      Display aspect ratio : 16:9
      Frame rate mode : Constant
      Frame rate : 24.000 FPS
      Color space : YUV
      Chroma subsampling : 4:2:0
      Bit depth : 8 bits
      Scan type : Progressive
      Default : Yes
      Forced : No
      DURATION : 00:02:29.651000000
      HANDLER_NAME : VideoHandler
   Audio #2
      ID : 2
      Format : Opus
      Codec ID : A_OPUS
      Duration : 2 min
      Channel(s) : 2 channels
      Channel positions : Front: L R
      Sampling rate : 48.0 kHz
      Compression mode : Lossy
      Delay relative to video : -7 ms
      Language : English
      Default : Yes
      Forced : No
      DURATION : 00:02:29.661000000

I thought it couldn't play .mkv so I converted File 2 to mp4 (using ffmpeg) which worked. But surprisingly, File 1 also worked without conversion so format isn't an issue. But then all the codecs look that same for me. What am I missing?
Thanks!

user1871: Both files that don't play feature Opus as the audio codec. As per this site, Opus is not one of the supported audio codecs.
Transcode the audio:
ffmpeg -i in.mkv -c:v copy out.mkv


17716: <p>I wanted to play UHD (4k) videos in my new LeTV (<a href="http://www.lemall.com/us/product/x355.html" rel="nofollow noreferrer">Super3 X55</a>). </p>

<p>So I used <a href="https://github.com/rg3/youtube-dl" rel="nofollow noreferrer">youtube-dl</a> to download 4k YouTube videos (which are humongous btw) but for some reason most of them do not play.</p>

<p>The TV's website specifically states:</p>

<blockquote>
  <p>HEVC/H.265 hardware video decoding, up to 4K@60fps</p>
</blockquote>

<p>But only a few files play. I'm thinking the issue is something to do with codecs or formats.</p>

<p>So I compared the info of files which <em>did</em> play with those that didn't. But I can't figure out the difference. Here are two files which played and two that didn't.</p>

<hr>

<h2>These two files played beautifully:</h2>

<p>File 1 :: GoPro video</p>

<pre><code>C:\Users\Hackathon\Videos\HD or 4k\GoPro\NA\NA - GoPro HERO4 - The Adventure of Life in 4K.mkv
   General
      Unique ID : 98713554682895442793938602234209693471 (0x4A438A01ACFC3EF5104AF4D6A778EF1F)
      Complete name : C:\Users\Hackathon\Videos\HD or 4k\GoPro\NA\NA - GoPro HERO4 - The Adventure of Life in 4K.mkv
      Format : Matroska
      Format version : Version 4 / Version 2
      File size : 581 MiB
      Duration : 4 min
      Overall bit rate mode : Variable
      Overall bit rate : 19.2 Mb/s
      Movie name : GoPro HERO4: The Adventure of Life in 4K
      Description : All around the world GoPro users are capturing incredible experiences, from the heart-stopping to the heartfelt. Into the caldron of an active volcano, the neon streets of Japan, a refuge for wild mustangs, scaling an iceberg, the world’s biggest dance party, or a whale rescue mission, GoPros have documented every moment. See how GoPro’s new line of our most advanced cameras ever allow you to beautifully and authentically capture and share the experiences that bring purpose, adventure, and joy to your life.

Shot 100% on the new GoPro HERO4 camera from http://GoPro.com.

The HERO4 features ultra high resolution quality of 4K at 30 frames per second + high frames rates at 1080p120. Incredible low light capabilities, including our new nightlapse setting. 2X the high fidelity sound. Faster processing. Protune settings that unlock manual control of many of your GoPro’s features, and so much more. Learn more and be inspired by the most advanced GoPro cameras yet: http://GoPro.com

It’s your life. BE A HERO.

MUSIC
"Run Boy Run" performed by Woodkid
Courtesy of Interscope Records under license from Universal Music Enterprises

FEATURED CHARACTERS

TOMORROWLAND (Boom, Belgium)
Erin Edenholm
Joanna Piotrowska
Steve Aoki
Krewella - Jahan Yousaf and Jasmine Yousaf
Dimitri Vegas
Like Mike

LAVA LAKE (Ambrym Island, Vanuatu)
Geoff Mackley
Brad Ambrose

ICEBERG CLIMB (Ilulissat, Greenland)
Klemen Premrl
Aljaz Anderle
Thierry Dubois

WILD MUSTANGS (Wells, Nevada)
Clay Nannini

JAPAN STREETS (Tokyo, Japan)
Akira Nakai
Shinichi Moroboshi
Nanami Tsukamoto

ORCA RESCUE (Whangarei, New Zealand)
Dr. Ingrid Visser
Terry Hardie
Dian and her two baby orca


SPECIAL THANKS
Tomorrowland (http://www.tomorrowland.com)
Michael Dujardin
Vanuatu Heli (http://www.vanuatuhelicopters.com)
Andy Martin
Black Diamond (http://www.blackdiamondequipment.com)
Madeline Pickens (http://mustangmonument.com) (http://savingamericasmustangs.org)
Orca Research Trust (http://orcaresearch.org)
Andy Casagrande (http://www.abc4explore.com/)
Steve Hathaway
Lily Kozman
      ARTIST : GoPro
      DATE : 20140929
      PURL : https://www.youtube.com/watch?v=wTcNtgA6gHs
   Video #1
      ID : 1
      Format : AVC
      Format/Info : Advanced Video Codec
      Format profile : High@L5.1
      Format settings, CABAC : No
      Format settings, ReFrames : 2 frames
      Codec ID : V_MPEG4/ISO/AVC
      Duration : 4 min
      Bit rate : 18.7 Mb/s
      Width : 3 840 pixels
      Height : 2 160 pixels
      Display aspect ratio : 16:9
      Frame rate mode : Constant
      Frame rate : 29.970 (30000/1001) FPS
      Color space : YUV
      Chroma subsampling : 4:2:0
      Bit depth : 8 bits
      Scan type : Progressive
      Bits/(Pixel*Frame) : 0.075
      Stream size : 566 MiB (97%)
      Default : Yes
      Forced : No
      Color range : Limited
      Color primaries : BT.709
      Transfer characteristics : BT.709
      Matrix coefficients : BT.709
      DURATION : 00:04:13.887000000
      HANDLER_NAME : VideoHandler
   Audio #2
      ID : 2
      Format : Vorbis
      Format settings, Floor : 1
      Codec ID : A_VORBIS
      Duration : 4 min
      Bit rate mode : Variable
      Bit rate : 128 kb/s
      Channel(s) : 2 channels
      Sampling rate : 44.1 kHz
      Compression mode : Lossy
      Stream size : 3.87 MiB (1%)
      Writing application : Google
      Language : English
      Default : Yes
      Forced : No
      DURATION : 00:04:13.906000000
</code></pre>

<p>File 2 :: Wonder Woman Trailer</p>

<pre><code>C:\Users\Hackathon\Music\iTunes\iTunes Media\Automatically Add to iTunes\WONDER WOMAN Trailer #2 [2017] (Ultra-HD 4K).mp4
   General
      Complete name : C:\Users\Hackathon\Music\iTunes\iTunes Media\Automatically Add to iTunes\WONDER WOMAN Trailer #2 [2017] (Ultra-HD 4K).mp4
      Format : MPEG-4
      Format profile : Base Media
      Codec ID : isom (isom/iso2/avc1/mp41)
      File size : 222 MiB
      Duration : 2 min
      Overall bit rate : 11.5 Mb/s
      Movie name : WONDER WOMAN Trailer #2 [2017] (Ultra-HD 4K)
      Writing application : Lavf57.48.103
      Cover : Yes
   Video #1
      ID : 1
      Format : AVC
      Format/Info : Advanced Video Codec
      Format profile : High@L5.1
      Format settings, CABAC : Yes
      Format settings, ReFrames : 4 frames
      Codec ID : avc1
      Codec ID/Info : Advanced Video Coding
      Duration : 2 min
      Bit rate : 11.3 Mb/s
      Width : 3 840 pixels
      Height : 2 160 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 : Progressive
      Bits/(Pixel*Frame) : 0.055
      Stream size : 219 MiB (99%)
      Writing library : x264 core 148 r2705 3f5ed56
      Encoding settings : cabac=1 / ref=3 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=6 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=23.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
      Language : English
   Audio #2
      ID : 2
      Format : AAC
      Format/Info : Advanced Audio Codec
      Format profile : LC
      Codec ID : 40
      Duration : 2 min
      Bit rate mode : Constant
      Bit rate : 129 kb/s
      Channel(s) : 2 channels
      Channel positions : Front: L R
      Sampling rate : 48.0 kHz
      Frame rate : 46.875 FPS (1024 spf)
      Compression mode : Lossy
      Stream size : 2.49 MiB (1%)
      Language : English
      Default : Yes
      Alternate group : 1
</code></pre>

<hr>

<h2>These two files did NOT play:</h2>

<p>"In A Nutshell" video:</p>

<pre><code>C:\Users\Hackathon\Videos\HD or 4k\Kurzgesagt – In a Nutshell\NA\NA - A New History for Humanity – The Human Era.mkv
   General
      Unique ID : 151773273920022300678100154581510254877 (0x722E78240BE681AAC8163B7BB9E3F11D)
      Complete name : C:\Users\Hackathon\Videos\HD or 4k\Kurzgesagt – In a Nutshell\NA\NA - A New History for Humanity – The Human Era.mkv
      Format : Matroska
      Format version : Version 4 / Version 2
      File size : 130 MiB
      Duration : 7 min
      Overall bit rate : 2 306 kb/s
      Movie name : A New History for Humanity – The Human Era
      Description : It is time to reframe how we think about our past.
We need a new year 0 for humanity. But which one should we choose and why?



http://www.youtube.com/timedtext_cs_panel?c=UCsXVk37bltHxD1rDPwtNM8Q&amp;amp;tab=2

A New History for Humanity – The Human Era
      Writing application : Lavf57.48.103
      Writing library : Lavf57.48.103 / Lavf57.48.103
      Comment : It is time to reframe how we think about our past.
We need a new year 0 for humanity. But which one should we choose and why?


THANKS A LOT TO OUR LOVELY PATRONS FOR SUPPORTING US:

Stuart Alldritt, Tasia Pele, Stan Serebryakov, Mike Janzen, Jason Heddle, August, Daniel Smith, Jonathan Herman, Rahul Rachuri, Piotr Gorzelany, Lisa Allcott, Горан Гулески, Eric Ziegast, Kean Drake, Friendly Stranger, NicoH, Adrian Rutkiewicz, Markus Klemm, Leandro Nascimento, Gary Chan, Shawhin Layeghi, Oscar Hernandez, Dale Prinsse, Vaclav Vyskocil, Sup3rW00t, Ryan Coonan, Tam Lerner, Dewi Cadat, Luis Aguirre, Andy McVey, Vexorum, Boris, Adam Wisniewski, Yannic Schreiber, Erik Lilly, Ellis, Dmitry Starostin, Akshay Joshi, Peter Tinti, kayle Clark, Mortimer Brewster, Marc Legault, Sumita Pal, Tarje Hellebust Jr., streetdragon95, Taratsamura, Sam Dickson, Bogdan Firicel, Saul Vera, Aaron Jacobs, Ben Arts, R B Dean, Kevin Beedon, Patrik Pärkinen, Duncan Graham, Johan Thomsen, Emily Tran, Adam Flanc, Adam Jermyn, Ali Uluyol

Help us caption &amp; translate this video!

http://www.youtube.com/timedtext_cs_panel?c=UCsXVk37bltHxD1rDPwtNM8Q&amp;amp;tab=2

A New History for Humanity – The Human Era
      ARTIST : Kurzgesagt – In a Nutshell
      DATE : 20161207
      PURL : https://www.youtube.com/watch?v=czgOWmtGVGs
   Video #1
      ID : 1
      Format : AVC
      Format/Info : Advanced Video Codec
      Format profile : High@L4.2
      Format settings, CABAC : Yes
      Format settings, ReFrames : 3 frames
      Codec ID : V_MPEG4/ISO/AVC
      Duration : 7 min
      Width : 1 920 pixels
      Height : 1 080 pixels
      Display aspect ratio : 16:9
      Frame rate mode : Constant
      Frame rate : 60.000 FPS
      Color space : YUV
      Chroma subsampling : 4:2:0
      Bit depth : 8 bits
      Scan type : Progressive
      Default : Yes
      Forced : No
      Color range : Limited
      Color primaries : BT.709
      Transfer characteristics : BT.709
      Matrix coefficients : BT.709
      DURATION : 00:07:52.447000000
      HANDLER_NAME : VideoHandler
   Audio #2
      ID : 2
      Format : Opus
      Codec ID : A_OPUS
      Duration : 7 min
      Channel(s) : 2 channels
      Channel positions : Front: L R
      Sampling rate : 48.0 kHz
      Compression mode : Lossy
      Delay relative to video : -14 ms
      Language : English
      Default : Yes
      Forced : No
      DURATION : 00:07:52.461000000
</code></pre>

<p>Finally a puppies video:</p>

<pre><code>C:\Users\Hackathon\Videos\HD or 4k\Jacob   Katie Schwarz\NA\NA - PUPPIES BATH IN 4K (ULTRA HD).mkv
   General
      Unique ID : 172223577613529861860930485370882755628 (0x81910DF562C189096C7EE7D95D3A0C2C)
      Complete name : C:\Users\Hackathon\Videos\HD or 4k\Jacob   Katie Schwarz\NA\NA - PUPPIES BATH IN 4K (ULTRA HD).mkv
      Format : Matroska
      Format version : Version 4 / Version 2
      File size : 311 MiB
      Duration : 2 min
      Overall bit rate : 17.4 Mb/s
      Movie name : PUPPIES BATH IN 4K (ULTRA HD)
      Description : To view this video in 4K select "Original" in the resolution menu. If you're having trouble with 4K playback, try using different browsers, like Internet Explorer, Firefox or Google Chrome.

Our friends just had puppies and we took the chance to film them this last weekend before they all left for new homes.

This video was filmed and edited at 4K (4096x2304) resolution, four times greater than regular 1080p HD. All 4K file are available upon request. Shot on Red Epic.

Follow us on twitter: http://www.twitter.com/jakeschwarz


Tech spec:
Red Epic (M642) w/ Ti Canon Mount
16-35mm &amp; 50mm L-Series Lens
Adobe Premiere CS6 and DaVinci Resolve

Question or business inquires:
contact@mysterybox.us

Copyright © 2014 Mystery Box, LLC. All Rights Reserved.
      Writing application : Lavf57.48.103
      Writing library : Lavf57.48.103 / Lavf57.48.103
      Comment : To view this video in 4K select "Original" in the resolution menu. If you're having trouble with 4K playback, try using different browsers, like Internet Explorer, Firefox or Google Chrome.

Our friends just had puppies and we took the chance to film them this last weekend before they all left for new homes.

This video was filmed and edited at 4K (4096x2304) resolution, four times greater than regular 1080p HD. All 4K file are available upon request. Shot on Red Epic.

Follow us on twitter: http://www.twitter.com/jakeschwarz


Tech spec:
Red Epic (M642) w/ Ti Canon Mount
16-35mm &amp; 50mm L-Series Lens
Adobe Premiere CS6 and DaVinci Resolve

Question or business inquires:
contact@mysterybox.us

Copyright © 2014 Mystery Box, LLC. All Rights Reserved.
      ARTIST : Jacob   Katie Schwarz
      DATE : 20120922
      PURL : https://www.youtube.com/watch?v=SMwxZO2UjBw
   Video #1
      ID : 1
      Format : AVC
      Format/Info : Advanced Video Codec
      Format profile : High@L5.1
      Format settings, CABAC : No
      Format settings, ReFrames : 2 frames
      Codec ID : V_MPEG4/ISO/AVC
      Duration : 2 min
      Width : 4 096 pixels
      Height : 2 304 pixels
      Display aspect ratio : 16:9
      Frame rate mode : Constant
      Frame rate : 24.000 FPS
      Color space : YUV
      Chroma subsampling : 4:2:0
      Bit depth : 8 bits
      Scan type : Progressive
      Default : Yes
      Forced : No
      DURATION : 00:02:29.651000000
      HANDLER_NAME : VideoHandler
   Audio #2
      ID : 2
      Format : Opus
      Codec ID : A_OPUS
      Duration : 2 min
      Channel(s) : 2 channels
      Channel positions : Front: L R
      Sampling rate : 48.0 kHz
      Compression mode : Lossy
      Delay relative to video : -7 ms
      Language : English
      Default : Yes
      Forced : No
      DURATION : 00:02:29.661000000
</code></pre>

<p>I thought it couldn't play .mkv so I converted File 2 to mp4 (using ffmpeg) which <em>worked</em>. But surprisingly, File 1 also worked without conversion so format isn't an issue. But then all the codecs look that same for me. What am I missing?</p>

<p>Thanks!</p>
 1871: <p>Both files that don't play feature Opus as the audio codec. As per this <a href="http://www.reviewcenter.in/4876/leeco-super3-x55-smart-tv-specifications-features-price/" rel="nofollow noreferrer">site</a>, Opus is not one of the supported audio codecs.</p>

<p>Transcode the audio:</p>

<pre><code>ffmpeg -i in.mkv -c:v copy out.mkv
</code></pre>
