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Autres articles (90)
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Le profil des utilisateurs
12 avril 2011, parChaque utilisateur dispose d’une page de profil lui permettant de modifier ses informations personnelle. Dans le menu de haut de page par défaut, un élément de menu est automatiquement créé à l’initialisation de MediaSPIP, visible uniquement si le visiteur est identifié sur le site.
L’utilisateur a accès à la modification de profil depuis sa page auteur, un lien dans la navigation "Modifier votre profil" est (...) -
Configurer la prise en compte des langues
15 novembre 2010, parAccéder à la configuration et ajouter des langues prises en compte
Afin de configurer la prise en compte de nouvelles langues, il est nécessaire de se rendre dans la partie "Administrer" du site.
De là, dans le menu de navigation, vous pouvez accéder à une partie "Gestion des langues" permettant d’activer la prise en compte de nouvelles langues.
Chaque nouvelle langue ajoutée reste désactivable tant qu’aucun objet n’est créé dans cette langue. Dans ce cas, elle devient grisée dans la configuration et (...) -
La sauvegarde automatique de canaux SPIP
1er avril 2010, parDans le cadre de la mise en place d’une plateforme ouverte, il est important pour les hébergeurs de pouvoir disposer de sauvegardes assez régulières pour parer à tout problème éventuel.
Pour réaliser cette tâche on se base sur deux plugins SPIP : Saveauto qui permet une sauvegarde régulière de la base de donnée sous la forme d’un dump mysql (utilisable dans phpmyadmin) mes_fichiers_2 qui permet de réaliser une archive au format zip des données importantes du site (les documents, les éléments (...)
Sur d’autres sites (12098)
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How to Match ASS Subtitle Font Size with Flutter Text Size for a 1080p Video ?
16 décembre 2024, par Mostafa FathiI’m working on a project where I need to synchronize the font size of ASS subtitles with the text size a user sees in a Flutter application. The goal is to ensure that the text size in a 1080p video matches what the user sees in the app.


What I've Tried :


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- Calculating font size using height ratio (PlayResY/DeviceHeight) :




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- I used the formula :




FontSize_ASS = FontSize_Flutter * (PlayResY / DeviceHeight)


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- While the result seemed logical, the final output in the video was smaller than expected.




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- Adding a scaling factor :




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- I introduced a scaling factor (around 3.0) to address the size discrepancy.
- This improved the result but still felt inconsistent and lacked precision.






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- Using force_style in FFmpeg :




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- I applied the force_style parameter to control the font size in FFmpeg directly.




ffmpeg -i input.mp4 -vf "subtitles=subtitle.ass:force_style='FontSize=90'" -c:a copy output.mp4


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- While it produced better results, it’s not an ideal solution as it bypasses the calculations in the ASS file.




- 

- Aligning
PlayResXandPlayResYin the ASS file :
I ensured that these parameters matched the target video resolution (1920×1080) :




PlayResX: 1920
PlayResY: 1080


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- Despite this adjustment, the font size didn’t align perfectly with the Flutter app text size.




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- Reading font metrics from the font file dynamically :
To improve precision, I wrote a function in Flutter that reads font metrics (units per EM, ascender, and descender) from the TTF font file and calculates a more accurate scaling factor :




Future readFontMetrics(
 String fontFilePath, 
 double originalFontSize,
) async {
 final fontData = await File(fontFilePath).readAsBytes();
 final fontBytes = fontData.buffer.asUint8List();
 final byteData = ByteData.sublistView(fontBytes);

 int numTables = readUInt16BE(byteData, 4);
 int offsetTableStart = 12;
 Map> tables = {};

 for (int i = 0; i < numTables; i++) {
 int recordOffset = offsetTableStart + i * 16;
 String tag =
 utf8.decode(fontBytes.sublist(recordOffset, recordOffset + 4));
 int offset = readUInt32BE(byteData, recordOffset + 8);
 int length = readUInt32BE(byteData, recordOffset + 12);

 tables[tag] = {
 'offset': offset,
 'length': length,
 };
 }

 if (!tables.containsKey('head') || !tables.containsKey('hhea'){
 print('Required tables not found in the font file.');
 return null;
 }

 int headOffset = tables['head']!['offset']!;
 int unitsPerEm = readUInt16BE(byteData, headOffset + 18);

 int hheaOffset = tables['hhea']!['offset']!;
 int ascender = readInt16BE(byteData, hheaOffset + 4);
 int descender = readInt16BE(byteData, hheaOffset + 6);

 print('unitsPerEm: $unitsPerEm');
 print('ascender: $ascender');
 print('descender: $descender');

 int nominalSize = unitsPerEm;
 int realDimensionSize = ascender - descender;
 double scaleFactor = realDimensionSize / nominalSize;
 double realFontSize = originalFontSize * scaleFactor;

 print('Scale Factor: $scaleFactor');
 print('Real Font Size: $realFontSize');

 return realFontSize;
}


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- This function dynamically reads the font properties (ascender, descender, and unitsPerEM) and calculates a scale factor to get the real font size. Despite this effort, discrepancies persist when mapping it to the ASS font size.




Question :
How can I ensure that the font size in the ASS file accurately reflects the size the user sees in Flutter ? Is there a reliable method to calculate or align the sizes correctly across both systems ? Any insights or suggestions would be greatly appreciated.


Thank you ! 🙏


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Unable to split audio using easy_audio_trimmer
27 juillet 2023, par Sana Wasimcan we use the easy_audio_trimmer package to split an audio ? I tried using the ffmpeg but it is conflicting with the above package and not work.


I tried splitting by using these functions and it gave an error at the FlutterFFmpeg() method and i cant find an alternative also the duration(filePath) in the command final durationResult = await flutterSound.duration(filePath) ; shows an error


Future<void> _splitAudio() async {
 setState(() {
 _progressVisibility = true;
 });

 // Get the application documents directory
 final appDocumentsDirectory = await getApplicationDocumentsDirectory();

 // Get the input audio file path
 final inputAudioPath = widget.file.path;

 // Get the output file names for the two parts
 final outputFileName1 = 'split_audio_part1.mp3';
 final outputFileName2 = 'split_audio_part2.mp3';

 // Get the output file paths for the two parts
 final outputPath1 = '${appDocumentsDirectory.path}/$outputFileName1';
 final outputPath2 = '${appDocumentsDirectory.path}/$outputFileName2';

 // Calculate the duration of the original audio
 final originalDuration = await _getAudioDuration(inputAudioPath);

 // Calculate the durations of the two parts
 final part1Duration = _startValue;
 final part2Duration = originalDuration - _endValue;

 // Construct the FFmpeg command to split the audio
 final ffmpeg = FlutterFFmpeg();
 final splitCommand = '-i $inputAudioPath -ss 0 -t $part1Duration -c copy $outputPath1 -ss $_endValue -t $part2Duration -c copy $outputPath2';

 try {
 // Execute the FFmpeg command to split the audio
 final int result = await ffmpeg.execute(splitCommand);

 if (result == 0) {
 setState(() {
 _progressVisibility = false;
 });
 debugPrint('Audio split successfully.');
 } else {
 setState(() {
 _progressVisibility = false;
 });
 debugPrint('Failed to split audio.');
 }
 } catch (error) {
 setState(() {
 _progressVisibility = false;
 });
 debugPrint('Error while splitting audio: $error');
 }
 }

 Future<int> _getAudioDuration(String filePath) async {
 final flutterSound = FlutterSound();
 final durationResult = await flutterSound.duration(filePath);
 return durationResult.inMilliseconds;
 }
</int></void>

Dependencies


path_provider: ^2.0.15
 ffmpeg_kit_flutter: ^5.1.0
 audioplayers: ^4.1.0
 flutter_sound: ^9.2.13


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FFMPEG : Converting from raw audio to audio/mp4 (audio is being converted with slow speed)
29 décembre 2017, par ValdirIf I convert from mp3 to mp4 directly everything works perfectly. But if I try to convert from raw pcm, the audio speed is slowed down.
I’ve tried the following (this works) :
ffmpeg -i mp3/1.mp3 -strict -2 final.mp4This doesn’t work as expected :
ffmpeg -f s16le -i final.raw -strict -2 -r 26 final.mp4With the following output :
Input #0, s16le, from 'final.raw':
Duration: 00:08:37.38, bitrate: 705 kb/s
Stream #0:0: Audio: pcm_s16le, 44100 Hz, 1 channels, s16, 705 kb/s
File 'final.mp4' already exists. Overwrite ? [y/N] y
Output #0, mp4, to 'final.mp4':
Metadata:
encoder : Lavf56.40.101
Stream #0:0: Audio: aac ([64][0][0][0] / 0x0040), 44100 Hz, mono, fltp, 128 kb/s
Metadata:
encoder : Lavc56.60.100 aac
Stream mapping:
Stream #0:0 -> #0:0 (pcm_s16le (native) -> aac (native))
Press [q] to stop, [?] for help
size= 8273kB time=00:08:37.38 bitrate= 131.0kbits/s
video:0kB audio:8185kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.073808%I’ve tried to set parameters like :
ffmpeg -ar 44100 -f s16le -i final.raw -strict -2 -r 26 final.mp4With no luck.
In order to get the PCM from mp3 I’m using nodejs lame decoder :
var decoder = new lame.Decoder({
channels: 2,
bitDepth: 16,
sampleRate: 44100,
bitRate: 128,
outSampleRate: 44100, // 22050
mode: lame.STEREO
});
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