Answers.Body: <p>The 3rd stream in your input is a regular stream. Attachments are basically extradata attached to streams.</p>
  
  <p>You would use</p>
  
  <pre><code>ffmpeg -i input.mp4 -map 0:2 -c copy -f data subs.txt
  </code></pre>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-12-03T00:38:55.087Z
Answers.Text: That created a blank .txt file. I can't get any subtitles to showup in vlc player either, it recognizes the stream tho, so maybe its supposed to be a blank file. What does the "-f data" do? I thought -f had something to do with generating raw data, not sure what "data" does though.
Answers.UserDisplayName: kite
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-12-03T04:55:12.780Z
Answers.Text: `data` muxer is for any data (binary/text) to be dumped while avoiding all automatic processing that ffmpeg may perform for streams identified as a video or audio type.
Answers.UserDisplayName: Gyan
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-11-26T16:09:53.423Z
Answers.LastActivityDate: 2019-11-26T16:09:53.423Z
Answers.UserDisplayName: Gyan
Body: <p>There's a video I need to view, foreign language film. I was checking it with ffmpeg, and it seemed legitimate except the third stream was something I've never seen before. I want to know what it is and how to view the stream's contents.</p>
  
  <p>I tried dumping it with</p>
  
  <pre><code>ffmpeg -dump_attachment:t:0 subs.txt -i input.mp4
  </code></pre>
  
  <p>Yet the file that was dumped is invisible...but showed up a number in the file folder. I'm using windows 8.1 and hidden folders/files are set to visible. Maybe my command is wrong and this is a subfile... instead of a information file..(i tried s:0 instead but no difference)? Or I can't dump this? Should I change from .txt to some other extension or what do I need to do to dump and view it?</p>
  
  <p>I just don't know what it is, and i want to know what it is. If we assume it's a subfile, I should be able to open it in a text editor right? So how can I do that...preferably a safe way of doing so.</p>
  
  <p><a href="https://i.sstatic.net/qVPi1.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/qVPi1.jpg" alt="enter image description here"></a></p>
  
Tags: <ffmpeg><subtitles>
Title: Unknown stream found in container (likely a subfile): need help identifying/opening it
UserDisplayName: kite
ThreadText: # Unknown stream found in container (likely a subfile): need help identifying/opening it
  
  (Asked by: username_0 on 2019-11-26)
  
  There's a video I need to view, foreign language film. I was checking it with ffmpeg, and it seemed legitimate except the third stream was something I've never seen before. I want to know what it is and how to view the stream's contents.
  
  I tried dumping it with
  
  ```
  ffmpeg -dump_attachment:t:0 subs.txt -i input.mp4
  
  ```
  
  Yet the file that was dumped is invisible...but showed up a number in the file folder. I'm using windows 8.1 and hidden folders/files are set to visible. Maybe my command is wrong and this is a subfile... instead of a information file..(i tried s:0 instead but no difference)? Or I can't dump this? Should I change from .txt to some other extension or what do I need to do to dump and view it?
  
  I just don't know what it is, and i want to know what it is. If we assume it's a subfile, I should be able to open it in a text editor right? So how can I do that...preferably a safe way of doing so.
  
  [![enter image description here](https://i.sstatic.net/qVPi1.jpg)](https://i.sstatic.net/qVPi1.jpg)
  
  **Tags:** ffmpeg, subtitles
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2019-11-26. Score: 0 | Accepted answer
  
  The 3rd stream in your input is a regular stream. Attachments are basically extradata attached to streams.
  
  You would use
  
  ```
  ffmpeg -i input.mp4 -map 0:2 -c copy -f data subs.txt
  
  ```
  
  > **Comments:**
  > **username_0**: That created a blank .txt file. I can't get any subtitles to showup in vlc player either, it recognizes the stream tho, so maybe its supposed to be a blank file. What does the "-f data" do? I thought -f had something to do with generating raw data, not sure what "data" does though.  
  > **username_1**: `data` muxer is for any data (binary/text) to be dumped while avoiding all automatic processing that ffmpeg may perform for streams identified as a video or audio type.  
  
  ---
  
  