<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>

CC BY-SA 4.0
2019-12-03T00:38:55.087Z
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.
kite
CC BY-SA 4.0
2019-12-03T04:55:12.780Z
`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.
Gyan
CC BY-SA 4.0
2019-11-26T16:09:53.423Z
2019-11-26T16:09:53.423Z
Gyan
<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>

<ffmpeg><subtitles>
Unknown stream found in container (likely a subfile): need help identifying/opening it
kite
# 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.

**Tags:** ffmpeg, subtitles


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## 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.  

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