Answers.Body: <p>This is certainly possible, and rather easy to do, for example with <a href="https://mkvtoolnix.download/" rel="nofollow noreferrer">MKVToolnix</a>, adding the second file as new source to current settings (just darg &amp; drop the files)</p>
  <p><a href="https://i.sstatic.net/fyr2u.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/fyr2u.png" alt="enter image description here" /></a></p>
  <p><a href="https://i.sstatic.net/0Gu6G.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/0Gu6G.png" alt="enter image description here" /></a></p>
  <p>Matroska video can handle multiple streams, and so can mp4. MKVToolnix gives only mkv as output I think. For various output formats a good  tool is <a href="http://dmsimpleapps.blogspot.com/2014/04/dmmediaconverter.html" rel="nofollow noreferrer">dmMediaConverter</a>, which is less known but is a great ffmpeg frontend.</p>
  <p><a href="https://i.sstatic.net/AKpOg.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/AKpOg.png" alt="enter image description here" /></a></p>
  <hr />
  <p>The output has the expected size of the two input sizes added up.</p>
  <p>As for playing the resulting movie and switching between the video streams, VLC can do it, as well as Gnome Mpv (in Linux). SMPlayer was less good (sometimes jumped forward when switching or just crashed). MPV with pseudo-gui has no option for the switch. (Tested in Linux.)</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-02-02T19:08:46.217Z
Answers.LastActivityDate: 2021-02-08T10:03:00.273Z
Answers.LastEditDate: 2021-02-08T10:03:00.273Z
Answers.UserDisplayName: cipricus
Answers.Body: <p>Yes. MPEG-4 Part 14 (the MP4 container format) supports any number of objects (e.g. video, audio and subtitle streams) and isn't limited to only one stream per content type.</p>
  
  <p>In practice however, you seldom see a video file that has multiple video streams, because the range of applications for this is very limited. I would also advise you not to put multiple video streams into one file, as (a) users don't expect it, many won't know how to switch the video track or not notice there is a second video track at all and (b) many players (soft- and hardware) aren't equipped to play files with multiple video streams and either won't have any option to switch between streams or fail to play the file completely.</p>
  
  <p>It is also more common to use Matroska (.mkv) containers for video files with multiple audio/subtitle streams, but even with those, you rarely see files with more than one video stream.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-03-16T11:14:06.163Z
Answers.Text: 1) do you know which video editors can handle such videos? Adobe Premiere , Sony Vegas or?... 
  
  2) will youtube convert such video file into 1-streamed file (at this moment, my typcal m4 files are converted by youtube to mpeg-4 10 AVC_
Answers.UserDisplayName: T.Todua
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-03-16T11:29:46.320Z
Answers.Text: Another disadvantage of multiple video streams in one file is (c) that it dramatically increases the filesize. To play one of the streams the player has to access the data for all of them at the same time.
Answers.UserDisplayName: stib
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-03-16T12:49:45.520Z
Answers.Text: @T.Todua No idea. As I said, in my experience most applications aren't built to handle multiple video streams because in practice there's really no application for them. You should be able to build a file with multiple video streams with ffmpeg, but what is YouTube supposed to do with it? It doesn't even have an option to switch between multiple Audio streams, let alone Video streams ... just create two seperate videos and be done with it
Answers.UserDisplayName: MoritzLost
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2018-08-02T21:52:20.047Z
Answers.Text: One application I think is storing footage from depth cameras (RGB-D). Synchronizing the two video tracks at a frame level could be tricky I suspect -- does .mkv support this?
Answers.UserDisplayName: thinkski
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-02-08T09:59:40.487Z
Answers.Text: @stib - The output size is not "increased", it is just equal to that of the  inputs. The same two streams take the same space whether in one file or in two.
Answers.UserDisplayName: cipricus
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-02-08T10:01:36.623Z
Answers.Text: @T.Todua - This is much simpler than it looks. I have posted an answer with two cross-platform opensource tools. As for players, the most common ones (VLC) can handle the multi-video-stream files.
Answers.UserDisplayName: cipricus
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-02-08T12:06:13.190Z
Answers.Text: @cipricus,yes that's true, but having multiple streams in a single file means that a much larger file has to be accessed, and the data rate is directly proportional to how many streams are muxed together. So instead of say two files, either of which has a data rate of X mbs, you now have a single file with a data rate of 2X mbs
Answers.UserDisplayName: stib
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-03-15T14:48:34.030Z
Answers.LastActivityDate: 2017-03-15T23:20:10.127Z
Answers.LastEditDate: 2017-03-15T23:20:10.127Z
Answers.UserDisplayName: MoritzLost
Body: <p>Is that possible, that a video (.mp4 or etc) had two video streams and we could to do work with each stream individually ? (like we do with 2 audio streams and we can remove any of them)..</p>
  
  <p>if so:</p>
  
  <p>1)  do you know which video editors can handle such videos? Adobe Premiere , Sony Vegas, DaVinci or ... ?</p>
  
  <p>2) At this moment, my typical MP4 files are converted by youtube (after upload) to i.e. <code>mpeg-4 10 AVC</code>. And will those 2-stream videos will be converted to 1-stream video anyway? (maybe I have to ask that to YT forum, right?)</p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-03-15T12:15:10.550Z
Comments.Text: Certainly can. MP4 files can contain any number of video, audio, subtitle and other data tracks.
Comments.UserDisplayName: stib
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-03-15T13:00:18.757Z
Comments.Text: In practice, yes. Although I'm sure the field storing the number of streams has a max limit of 2^16 or 32.
Comments.UserDisplayName: Gyan
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2017-03-15T23:43:27.667Z
Comments.Text: @T.Todua, out of curiosity, what is your use case?
Comments.UserDisplayName: Michael Liebman
Tags: <video><audio>
Title: Can video have multiple streams (like it has 2 audio streams)
UserDisplayName: T.Todua
ThreadText: # Can video have multiple streams (like it has 2 audio streams)
  
  (Asked by: username_0 on 2017-03-15)
  
  Is that possible, that a video (.mp4 or etc) had two video streams and we could to do work with each stream individually ? (like we do with 2 audio streams and we can remove any of them)..
  
  if so:
  
  1) do you know which video editors can handle such videos? Adobe Premiere , Sony Vegas, DaVinci or ... ?
  
  2) At this moment, my typical MP4 files are converted by youtube (after upload) to i.e. `mpeg-4 10 AVC`. And will those 2-stream videos will be converted to 1-stream video anyway? (maybe I have to ask that to YT forum, right?)
  
  **Tags:** video, audio
  
  > **Comments:**
  > **username_1**: Certainly can. MP4 files can contain any number of video, audio, subtitle and other data tracks.  
  > **username_2**: In practice, yes. Although I'm sure the field storing the number of streams has a max limit of 2^16 or 32.  
  > **username_3**: @username_0, out of curiosity, what is your use case?  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_5 on 2017-03-15. Score: 10 | Accepted answer
  
  Yes. MPEG-4 Part 14 (the MP4 container format) supports any number of objects (e.g. video, audio and subtitle streams) and isn't limited to only one stream per content type.
  
  In practice however, you seldom see a video file that has multiple video streams, because the range of applications for this is very limited. I would also advise you not to put multiple video streams into one file, as (a) users don't expect it, many won't know how to switch the video track or not notice there is a second video track at all and (b) many players (soft- and hardware) aren't equipped to play files with multiple video streams and either won't have any option to switch between streams or fail to play the file completely.
  
  It is also more common to use Matroska (.mkv) containers for video files with multiple audio/subtitle streams, but even with those, you rarely see files with more than one video stream.
  
  > **Comments:**
  > **username_0**: 1) do you know which video editors can handle such videos? Adobe Premiere , Sony Vegas or?...   2) will youtube convert such video file into 1-streamed file (at this moment, my typcal m4 files are converted by youtube to mpeg-4 10 AVC_  
  > **username_1**: Another disadvantage of multiple video streams in one file is (c) that it dramatically increases the filesize. To play one of the streams the player has to access the data for all of them at the same time.  
  > **username_5**: @username_0 No idea. As I said, in my experience most applications aren't built to handle multiple video streams because in practice there's really no application for them. You should be able to build a file with multiple video streams with ffmpeg, but what is YouTube supposed to do with it? It doesn't even have an option to switch between multiple Audio streams, let alone Video streams ... just create two seperate videos and be done with it  
  > **username_6**: One application I think is storing footage from depth cameras (RGB-D). Synchronizing the two video tracks at a frame level could be tricky I suspect -- does .mkv support this?  
  > **username_4**: @username_1 - The output size is not "increased", it is just equal to that of the  inputs. The same two streams take the same space whether in one file or in two.  
  > **username_4**: @username_0 - This is much simpler than it looks. I have posted an answer with two cross-platform opensource tools. As for players, the most common ones (VLC) can handle the multi-video-stream files.  
  > **username_1**: @username_4,yes that's true, but having multiple streams in a single file means that a much larger file has to be accessed, and the data rate is directly proportional to how many streams are muxed together. So instead of say two files, either of which has a data rate of X mbs, you now have a single file with a data rate of 2X mbs  
  
  ---
  
  ### Answer by username_4 on 2021-02-02. Score: 1
  
  This is certainly possible, and rather easy to do, for example with [MKVToolnix](https://mkvtoolnix.download/), adding the second file as new source to current settings (just darg & drop the files)
  
  [![enter image description here](https://i.sstatic.net/fyr2u.png)](https://i.sstatic.net/fyr2u.png)
  
  [![enter image description here](https://i.sstatic.net/0Gu6G.png)](https://i.sstatic.net/0Gu6G.png)
  
  Matroska video can handle multiple streams, and so can mp4. MKVToolnix gives only mkv as output I think. For various output formats a good tool is [dmMediaConverter](http://dmsimpleapps.blogspot.com/2014/04/dmmediaconverter.html), which is less known but is a great ffmpeg frontend.
  
  [![enter image description here](https://i.sstatic.net/AKpOg.png)](https://i.sstatic.net/AKpOg.png)
  
  ---
  
  The output has the expected size of the two input sizes added up.
  
  As for playing the resulting movie and switching between the video streams, VLC can do it, as well as Gnome Mpv (in Linux). SMPlayer was less good (sometimes jumped forward when switching or just crashed). MPV with pseudo-gui has no option for the switch. (Tested in Linux.)
  
  
  ---
  
  