Record file m4a doesn't upload to backend on android flutter

Question

so I was trying to upload files (png, pdf etc) to backend endpoint and it works on both android and iOS and there's a recorder in the app it returns m4a files when I try to upload the m4a files using the same function it works on iOS and the file gets uploaded but it doesn't work on android Do you know why is that?

Here's the recorder code:

  final recorder = Record();
  record() async {
    bool recording = await recorder.isRecording();
    if (recording) {
      String? path = await recorder.stop();
      await recorder.dispose();
      if (path != null) {
        attachments ??= [];
        File file = File(Platform.isIOS ? path.substring(7) : path);
        bool fileExits = await file.exists();
        if (fileExits) {
          attachments?.add(file);
        }
        setState(() {
          isRecording = false;
        });
      }
    } else {
      if (await recorder.hasPermission()) {
        setState(() {
          isRecording = true;
        });
        await recorder.start(
          encoder: AudioEncoder.aacLc,
          bitRate: 128000,
        );
        await Future.delayed(const Duration(minutes: 3), () async {
          if (await recorder.isRecording()) {
            String? path = await recorder.stop();
            await recorder.dispose();
            if (path != null) {
              attachments ??= [];
              File file = File(Platform.isIOS ? path.substring(7) : path);
              bool fileExits = await file.exists();
              if (fileExits) {
                attachments?.add(file);
              }
              setState(() {
                isRecording = false;
              });
            }
          }
        });
      }
    }
  }

Here's the function:

static Future<String?> uploadFile(File file, String token) async {
    // final fileLength = await image.length();
    String? imageURL;
    var request =
        http.MultipartRequest('POST', Uri.parse(APIEndPoints.uploadFiles));
    request.headers['Authorization'] = 'Bearer $token';
    request.headers['Content-Type'] = 'application/json';
    request.files.add(await http.MultipartFile.fromPath('file', file.path));
    http.StreamedResponse res = await request.send();
    String responseBody = await res.stream.bytesToString();
    if (res.statusCode == 200) {
      imageURL = '${APIEndPoints.baseUrl}/${jsonDecode(responseBody)['url']}';
    }
    print(res.statusCode);
    print(responseBody);
    return imageURL;
  }

Answer 1

I use the Record Plugin and will show you how I do it. I save the file in the temporary directory.

You get temporary directory with Path Provider.

final tempDir = await getTemporaryDirectory();

Then use the dir and set path for the temporary file.

await _recorder.start(
  const RecordConfig(),
  path: '${tempDir.path}/temp-audio.m4a',
);

and when the audio stops, you use the path from the recorder.

final path = await _recorder.stop();

Also, for when recorder starts and stops, I wait for about 400 milliseconds. I found that there is some delay, which I didn't delve into yet. The full code is below for your reference.

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:path_provider/path_provider.dart';
import 'package: record/record.dart';

class RecorderWidget extends StatefulWidget {
  const RecorderWidget({super.key});

  @override
  State<RecorderWidget> createState() => _RecorderWidgetState();
}

class _RecorderWidgetState extends State<RecorderWidget> {
  final _recorder = AudioRecorder();

  bool _isRecording = false;

  @override
  void initState() {
    super.initState();
  }

  @override
  void dispose() {
    _recorder.dispose();
    super.dispose();
  }

  Future<void> _start() async {
    try {
      if (await _recorder.hasPermission()) {
        final tempDir = await getTemporaryDirectory();
        await _recorder.start(
          const RecordConfig(),
          path: '${tempDir.path}/temp-audio.m4a',
        );
        // Just wait a while until recorder is properly loaded
        await Future.delayed(const Duration(milliseconds: 400));
        bool isRecording = await _recorder.isRecording();
        setState(() {
          _isRecording = isRecording;
        });
      }
    } catch (e) {
      debugPrint(e.toString());
    }
  }

  Future<void> _stop() async {
    final path = await _recorder.stop();
    setState(() => _isRecording = false);
    if (path != null) {
      // some delay just to make sure that file is saved properly
      await Future.delayed(const Duration(milliseconds: 400));
      // do something with path
    }
  }

  @override
  Widget build(BuildContext context) {
    // display recorder stuff
    return Container();
  }
}