I'm writing in raw PHP on Linux using the tcpdf library.
The core question is that while creating a PDF with tcpdf I'd also like to kick off an audio file for the user...but tcpdf considers that TCPDF ERROR: Some data has already been output, can't send PDF file so I'm looking for a way to play an audio file at PDF generation without tcpdf considering that 'interfering output'.
I can successfully generate my wanted PDF within my browser using the tcpdf library and calls. But I would also like to play an audio when this happens - that might say "This is your generated PDF. You can print it now...etc"
So I'm wanting to put the HTML audio syntax within my php script.
However if I try to include an audio clause before the tcpdf->output, tcpdf will play the audio but say that output has happened before the tcpdf output and will not generate the PDF image. Flow stops after the tcpdf->output command - it successfully generates the PDF but it does not return for additional lines so I can't place the audio line after the output call.
So I guess I'm looking for a "hidden" audio although I've tried hidden attributes within the HTML audio syntax but still tcpdf flags it as "output has happened". Thank you.
Well, obviously, you can do that simply by
generate the PDF into file (not to the client directly -- 'F' switch).
output your audio file to the client and let it platy
output a link/Javascript redirection to the generated PDF file.
Because you didn't provide any code in your question I do not provide any either, but I believe it is already understandable.
Related
I am using javascript to capture audio data from MediaRecorder, and base64 encode it so I can send it back to the web server where it can be saved for later playback.
data:audio/webm;codecs=opus;base64,GkXfo59ChoEBQveBA...(too much data to post, but you get the idea)
I can put that data into an HTML5 audio element's .src field, and play it back on a Chrome browser just fine. But Safari can't handle the data in that format, I guess it doesn't support the opus codec.
One solution for me would be to figure out how to write the audio data into a properly formatted .webm container file, and then use ffmpeg.exe to convert it to some other Safari friendly format.
But I don't know the file format for .webm file - I'm looking for tips or guidance how to write such a .webm file.
Anybody have any suggestions, libraries, or tips to write data like above to a .webm file? I prefer a C# .net answer, but javascript will also do, or any examples are appreciated.
Well, I got a tip from smart developer (earnabler) that if I stripped off the header portion of the content:
"data:audio/webm;codecs=opus;base64,"
and decoded just the base64 portion:
"GkXfo59ChoEBQveBA...(too much data to post, but you get the idea)"
...back to binary (example in C#):
byte[] decodedBinaryData;
decodedBinaryData = Convert.FromBase64String(encodedBase64String);
...and wrote that binary to a file with a matching file extension (.webm in this example), that the file would be a properly formatted file of that type understandable by other media software.
Lo and behold, it was! I could play the file in MediaPlayer, or QuickTime, or whatever, and could use FFMPEG to convert it to other types.
So that gives me a pathway to save/use/convert the media in many ways. Problem solved.
I'm building a project where people can upload files, I would like to then display those files in a browser where people can interact with them (vote, comment etc)
However, this means I need to programatically build the html depending on the format of the video or image. Is there a way to feed a file (or filename) into a library, and determine whether I need to display it in a video element or an image element? Even a list of video formats vs image formats would help but I haven't seen anything in regards to that.
No module can reliably determine the file type. The user could either change the extension or even the magic number of the file to obfuscate it. The only reliable way it to try to pass file to some image / video transcoder to let it decide or error out if the format is invalid. This way you know you are working with known formats since all files are transcoded to your specific extensions. That could be mp4 or png. I recommend using handbrake for videos and sharp for images. Leaving the NPM links down below:
https://www.npmjs.com/package/handbrake-js
https://www.npmjs.com/package/sharp
I am working on a module which uploads images, pdfs, audio and video files. I mainly covered all the validations in it but i am stuck at one point where i cannot detect the header of the video/audio file. It is when i change the type of any file, like changed the .JS to mp3 or mp4. Is there any packages in nodeJS which can detect the file signature or header?
Thanks in advance.
If you can not/do not, want to check by the filename extension you will have to parse the file using an appropriate media inspector.
To list a few:
file-type
mux.js
.
I am trying to understand how mpd file plays and i am referring to the following data set:
http://www-itec.uni-klu.ac.at/ftp/datasets/mmsys12/Valkaama/MPDs/Valkaama_1s_act_isoffmain_DIS_23009_1_v_2_1c2_2011_08_30.mpd
In mpd file format there is segment base consists of mp4 chunk and within it has chunk list with extension .m4s.I downloaded mpd file using :
http://www-itec.uni-klu.ac.at/ftp/datasets/mmsys12/Valkaama/valkaama_1s/valkaama_1s_50kbit/valkaama_50kbit_dash.mp4
and m4s chunk by following link:
http://www-itec.uni-klu.ac.at/ftp/datasets/mmsys12/Valkaama/valkaama_1s/valkaama_1s_50kbit/valkaama_1s1.m4s
I tried to play both mp4 and m4s in vlc player but not able to play any of these two so i want to ask which of the chunk links in the mpd file forma i can be able to play standalone in vlc player.
Please correct me if any of my observations is wrong:
Regards
Mayank
MPD file is just a index of streams with various formats in order to adapt to your bandwidth, to get more information follow the links of the other answers here.
It's possible to download all streams and merge them into a single file, you could achieve this by using youtube-dl:
youtube-dl http://URL/TO/manifest.mpd
You can get more information in https://stackoverflow.com/a/39931712/1522342.
Also, VLC 3.0.0+ can play that kind of file from a url, just open VLC, use the shortcut CTRL+N, paste the url and enjoy.
A DASH player plays an MPD by selecting a Period, and in the Period one or more AdaptationSet, and then one Representation per AdaptationSet. For the chosen Representation, it downloads and passes the intialization segment and some media segments to the media engine. As indicated by others you can simulate that by concatenating (simply using caton Linux).
The MPEG-DASH standard requires that initialization segments (in your case the mp4 file) contain no data. This is because when switching the player might use several times the initialization segment. You can open it in a player but it does not contain any media.
For m4s files, they contain media data but they cannot be interpreted without the associated initialization segment.
you can download init segment (SegmentBase/Initialization#sourceURL) and all media segments (SegmentList/SegmentURL#media) and concatenate everything (e.g. with the copy command on windows). The result should be playable on VLC. This has to be done for audio and video separately. In the next step you can then use MP4Box or similar tools to mux audio and video.
Alternatively you can use www.dash-downloader.com to download everything in one step. The page will display some log explaining what it's doing. That might be helpfull.
(full disclosure: that's my website).
I dont think it is possible to play any of the files in a standalone player. The mp4 is the init segment which is required to decode the .m4s media segments. I dont think there is an option in the vlc player to map an init segment to multiple media segments. Nevertheless you can try a Dash player to play the manifest file. For instance dash.js
Initialization segment: A sequence of bytes that contain all of the initialization information required to decode a sequence of media segments. This includes codec initialization data, Track ID mappings for multiplexed segments, and timestamp offsets (e.g. edit lists).
Media segment: A sequence of bytes that contain packetized & timestamped media data for a portion of the media timeline. Media segments are always associated with the most recently appended initialization segment.
Source: http://www.w3.org/TR/media-source/#init-segment
I'm using sox to convert some mp3 files to wav for a project. The problem is that the software that plays the files does not have the media name for the element it is playing. I can't seem to find a win32 cli tool to read the header of the wav file and write what I need to it.
Sox will read the header but it's not showing the title of the media element that was inserted with the old software I used. I just couldnt automate it or I would have used it instead.
I have determined the info is written in either CART CHUNK section or just to the file headers. I can't figure out to write my own data there.
The way I was able to do this was with this project: https://github.com/JamesHeinrich/getID3