How to get audio duration in dart (not flutter)? - dart

I need to get audio duration (from file and url) in the dart package (NOT IN FLUTTER APP).
When I am trying to use packages from the pub.dev (like just_audio or similar) I receive an error like next:
/.flutter/packages/flutter/lib/src/services/binary_messenger.dart:6:8: Error: Not found: 'dart:ui'
So do you know the way how to get the duration in pure dart?

If you want to work only with mp3 files, you are lucky and you can use this package: mp3_info: ^0.2.0.
Code example:
//url
var url = Uri.parse('https://some_path/file.mp3');
var response = await http.get(url);
final mp3 = MP3Processor.fromBytes(response.bodyBytes);
//file
// final mp3 = MP3Processor.fromFile(File('path_to_file'));
print(mp3.bitrate);
print(mp3.duration);
But if you need to work with other formats, you have to parse the file's byte data according to audio formats specs... or you can try to find some c/c++ libraries and use them through ffi.

Related

find and share a downloaded video on Flutter ios without going through picker?

I have a Flutter app that can view mp4 files from a URL. (Using a video controller playing directly from the URL.) I want the user to be able to share them if they wish. As best I can tell the file has to actually exist on the device so I have broken down the steps for now into download file, invoke share.
I'm using this guide: https://retroportalstudio.medium.com/saving-files-to-application-folder-and-gallery-in-flutter-e9be2ebee92a
I need to work on ios and android. The problem is that on ios neither the filename I get from the dio downloader nor the ImageGallerySaver seem to "work" when passed to the system ShareSheet.
I'm using the flutter extensions dio, share_plus, cross_file, image_gallery_saver as I've seen recommended in various places.
File saveFile = File(directory.path + "/$fileName");
developer.log("starting download...");
await dio.download(url, saveFile.path,
onReceiveProgress: (value1, value2) {
developer.log("got progress " + value1.toString());
setState(() {
downloadProgress = value1 / value2;
});
});
_permaFile = saveFile.path;
if (Platform.isIOS) {
var galleryResult = await ImageGallerySaver.saveFile(saveFile.path,
isReturnPathOfIOS: true);
developer.log("gallery save result = " + galleryResult.toString());
_permaFile = galleryResult['filePath'];
}
After getting a directory we use dio to download the file, do some log chirping, and then save the name to an object member called _permaFile.
Then the share button triggers:
void _shareAction() async {
final box = context.findRenderObject() as RenderBox?;
final files = <XFile>[];
if (_permaFile == null) {
return;
}
developer.log("sharing file: " + _permaFile.toString());
files.add(XFile(_permaFile!));
await Share.shareXFiles(files,
text: "Event",
// subject: "Subject for Event",
sharePositionOrigin: box!.localToGlobal(Offset.zero) & box.size);
}
This works on android device... after I download I hit share, and I can share the video to a third-party app like WhatsApp.
On ios the ShareSheet is invoked but when I share I only get the text "Event", not the video file that goes along with it.
Note that I have tried both results... setting the _permaFile to be what comes back from ImageGallerySaver but also just using what the dio downloader gives back.
Note also that the ImageGallerySaver seems to work: the video really does land and is there in the ios video lib. If I go into the Photos app I can share from there to WhatsApp and have the video get sent.
In each case I get errors like this:
[ShareSheet] error fetching item for URL:file:/var/mobile/Media/DCIM/100APPLE/IMG_0021.MP4 -- file:/// : (null)
[ShareSheet] error fetching file provider domain for URL:file:/var/mobile/Media/DCIM/100APPLE/IMG_0021.MP4 -- file:/// : (null)
[ShareSheet] error loading metadata for
documentURL:file:/var/mobile/Media/DCIM/100APPLE/IMG_0021.MP4 --
file:/// error:Error Domain=NSFileProviderInternalErrorDomain Code=0
"No valid file provider found from URL
file:/var/mobile/Media/DCIM/100APPLE/IMG_0021.MP4 -- file:///."
UserInfo={NSLocalizedDescription=No valid file provider found from URL
file:/var/mobile/Media/DCIM/100APPLE/IMG_0021.MP4 -- file:///.}
In order to test this further I built the share_plus demo app:
https://github.com/fluttercommunity/plus_plugins/tree/main/packages/share_plus/share_plus
I modified it to share videos to see what was different. The share plus example (sp_example) works for sharing videos that have been selected by the picker.
For this reason I think the problem is something I'm missing about ios video filenames/formats and possibly a built-in conversion step that happens.
Here are what the filenames look like that I see in my app:
dio download result:
file:///var/mobile/Containers/Data/Application/223BF2B9-DDF0-490E-932F-09D5F03B98B3/Library/Caches/test.mp4
ImageGallerySaver result:
file:///var/mobile/Media/DCIM/100APPLE/IMG_0019.MP4
This is what video filenames look like when they are picked and shared in sp_example:
/private/var/mobile/Containers/Data/Application/E5CB4D7C-6CDF-4AA2-8134-C4322ED7C886/tmp/trim.E6633D68-44E3-4853-A29E-A71AC95A0913.MOV
Note that it has been converted to MOV extension and the user gets trim step right in the picker that results in trim in the name.
For my purposes I don't want to go through the picker, the user is on the screen showing the video and they shouldnt have to repick, so where do I get the post-conversion ios filename that references what I just saved?

Can Google's Speech API accept an external Video URL?

I recently figured out that Google's Vision API can accept an external image URL and I was curious if anyone knew if Google's Speech could accept an external video URL such as a YouTube video?
The code I have in my mind would look something like this:
def transcribe_gcs(yotube_url):
"""Asynchronously transcribes the audio file specified by the gcs_uri."""
from google.cloud import speech
from google.cloud.speech import enums
from google.cloud.speech import types
client = speech.SpeechClient()
audio = types.RecognitionAudio(uri=youtube_url) # swapped out gcs_uri with youtube_url
config = types.RecognitionConfig(
encoding=enums.RecognitionConfig.AudioEncoding.FLAC,
# sample_rate_hertz=16000,
language_code='en-US')
operation = client.long_running_recognize(config, audio)
print('Waiting for operation to complete...')
response = operation.result(timeout=90)
# Each result is for a consecutive portion of the audio. Iterate through
# them to get the transcripts for the entire audio file.
for result in response.results:
# The first alternative is the most likely one for this portion.
print(u'Transcript: {}'.format(result.alternatives[0].transcript))
print('Confidence: {}'.format(result.alternatives[0].confidence))
I was curious if anyone knew if Google's Speech could accept an
external video URL such as a YouTube video?
It needs to be a local path to your audio file (less than 1 min audio file) or GCS URI for audio file longer than 1 minute. What you're thinking is not possible, the audio/video file needs to be in GCS.
I think you can achieve this by streaming same video (for example on wowza or on any server of your choice.) and then simply extract audio using lets say ffmpeg and pass this to google. It should work. use StreamingRecognizeRequest instead of RecognitionAudio.

Adding metadata to generated audio file

I'm generating an audio file programmatically, and I'd like to add metadata to it, such as the title and artist. I don't particularly care what format the file is written in, as long as AVPlayer will read it and send it to the playing device. (The whole goal is to send this generated audio and its track name to a Bluetooth device. I'm happy to explore easier ways to achieve this on iPhone that don't require writing the file or adding metadata directly to the file.)
So far I've discovered that AVAssetWriter will often just throw away metadata that it doesn't understand, without generating errors, so I'm stumbling a bit trying to find what combinations of file formats and keys are acceptable. So far I have not found a file format that I can auto-generate that AVAssetWriter will add any metadata to. For example:
let writer = try AVAssetWriter(outputURL: output, fileType: .aiff)
let title = AVMutableMetadataItem()
title.identifier = .commonIdentifierTitle
title.dataType = kCMMetadataBaseDataType_UTF8 as String
title.value = "The Title" as NSString
writer.metadata = [title]
// setup the input and write the file.
I haven't found any combination of identifiers or fileTypes (that I can actually generate) that will include this metadata in the file.
My current approach is to create the file as an AIFF, and then use AVAssetExportSession to rewrite it as an m4a. Using that I've been able to add enough metadata that iTunes will show the title. However, Finder's "File Info" is not able to read the title (which it does for iTunes m4a files). My assumption is that if it doesn't even show up in File Info, it's not going to be sent over Bluetooth (I'll be testing that soon, but I don't have the piece of hardware I need handy).
Studying iTunes m4a files, I've found some tags that I cannot recreate with AVMetadataItem. For example, Sort Name (sonm). I don't know how to write tags that aren't one of the known identifiers (and I've tested all 263 AVMetadataIdentifiers).
With that background, my core questions:
What metadata tags are read by AVPlayer and sent to Bluetooth devices (i.e. AVRCP)?
Is it possible to write metadata directly with AVAssetWriter to a file format that supports Linear PCM (or some other easy-to-generate format)?
Given a known tag/value that does not match any of the AVMetadataIdentifiers), is it possible to write it in AVAssetExportSession?
I'll explore third-party id3 frameworks later, but I'd like to achieve it with AVFoundation (or other built-in framework) if possible.
I've been able to use AVAssetWriter to store metadata values in a .m4a file using the iTunes key space:
let songID = AVMutableMetadataItem()
songID.value = "songID" as NSString
songID.identifier = .iTunesMetadataSongID
let songName = AVMutableMetadataItem()
songName.value = "songName" as NSString
songName.identifier = .iTunesMetadataSongName
You can write compressed .m4a files directly using AVAssetWriter by specifying the correct settings when you set up the input object, so there’s no need to use an intermediate AIFF file.

Blackberry java radio streaming

I'm developing a radio app for BB 5.0 in java. I don't find a way to play the radio from the url stream address that I have. I use multiple formats but nothing works (.pls, .aac, .m3u). I get a RuntimeException every time I try to play the stream. The content is ok, I've checked it.
InputStream stream = Connector.openInputStream(urlPlay);
StreamConnection streamConnection = (StreamConnection) Connector.open(urlPlay, Connector.READ);
InputStream readAhead = streamConnection.openDataInputStream();
byte[] audioData = new byte[500];
readAhead.read(audioData,0,audioData.length);
ByteArrayInputStream in2 = new ByteArrayInputStream(audioData);
player = javax.microedition.media.Manager.createPlayer(in2, "audio/aac");
System.out.println("REALIZE");
player.realize();
System.out.println("PREFETCH");
player.prefetch();
System.out.println("START");
player.start();
Edit:
When I use a URL from my .pls file I hear a little bit of my streaming but It stops immediately.
I suspect the problem is that you are trying to play playlist files instead of an actual stream. Generally, you need to parse those files yourself to get the real stream URLs.
If you open up that .m3u file, you will see that it is just a list of URLs. Take one of those URLs and then try it. Also, be sure you are setting the right content type. You can determine what that type is with cURL or VLC.

How to extract the song name from a live audio stream on the Blackberry Storm?

HI
I am new to Blackberry.
I am developing an application to get the song name from the live audio stream. I am able to get the mp3 stream bytes from the particular radioserver.To get the song name I add the flag "Icy-metadata:1".So I am getting the header from the stream.To get the mp3 block size I use "Icy-metaInt".How to recognize the metadatablocks with this mp3 block size.I am using the following code.can anyone help me to get it...Here the b[off+k] is the bytes that are from the server...I am converting whole stream in to charArray which is wrong, but how to recognize the metadataHeaders according to the mp3 block size..
b[off+k] = buffers[PlayBuf]PlayByte];
String metaSt = httpConn.getHeaderField("icy-metaint");
metaInt=Integer.parseInt(metaSt);
for (int i=0;i<b[off+k];i++)
{
metadataHeader+=(new String(b)).toCharArray();
System.out.println(metadataHeader);
metadataLength--;
Blackberry has no native regex functionality; I would recommend grabbing the regexp-me library (http://code.google.com/p/regexp-me/) and compiling it into your code. I've used it before and its regex support is pretty good. I think the regex in the code you posted would work just fine.

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