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• How to add watermark to video in Flutter using Flutter_ffmpeg

  14 mai 2021, par user433575

  I cannot figure out why my ffmpeg commands aren't working...

  


    Future<void> watermark(filePath, width, height) async {&#xA;&#xA;final String outPath = &#x27;watermarked.mp4&#x27;;&#xA;final String inputVideo =&#xA;    await rootBundle.loadString(&#x27;assets/ffmpeg/demo.mov&#x27;);&#xA;final String inputWatermark = await rootBundle&#xA;    .loadString(&#x27;assets/ffmpeg/video_overlay.png&#x27;);&#xA;final arguments =&#xA;    &#x27;-i $inputVideo -i $inputWatermark -filter_complex overlay=10:10 -codec:a copy $outPath&#x27;;&#xA;&#xA;&#xA;final int rc = await FlutterFFmpeg().execute(arguments);&#xA;assert(rc == 0);&#xA;print("outPath $outPath");&#xA;&#xA;uploadFile(outPath, "gallery");&#xA;</void>

  


  }

  


  Thanks

  


• Best intra-frame codec for editing ? Having color issues with DNxHR and serious sync issues with Prores

  23 janvier 2020, par Raulo1985

  I have a couple of questions regarding intra-frame codecs for editing purposes (in Premiere Pro).

  A LITTLE CONTEXT :

  I ripped a HDR movie to a MP4 container some months ago, using H.264 as codec (high 10, level 5, UHD, YUV, subsampling 4:2:0). The video looks great, as it should. Now I want to edit a trailer for that movie (I edit in Adobe Premiere Pro, current version), and for fast playback I need to work with proxies or transcode the source file to an intra-frame non long GOP file and use it as the source file (hopefully as lossless as that transcoding step can be). I tried for several days to transcode the source file to DNxHR 444 10 bits (using FFmpeg and then Adobe Media Encoder), but the result was always a video with the colors messed up (sometimes very washed out, sometimes over saturated).

  FFprobe of the resulting DNxHR file said that the color space was BT709 (source file is obviously BT2020), and I don’t know why. The transcoding involved upsampling since the source file is 4:2:0 and DNxHR doesn’t support it, but I tried upsampling to 4:4:4 and also to 4:2:2, and both of those files looked exactly the same to me, and very different from the original footage (so, I don’t think upsampling is the cause of the color issue, but maybe the apparent color space change or something wrong with the metadata). The results were the same when transcoding with Adobe Media Encoder. Anyway, I seem to have given up transcoding to DNxHR and use it as the source file, unless someone has an idea of what’s causing this problem. I could have worked with the source file for exporting and DNxHR LB for proxies, but there were sync issues (between source file and proxy) that defeated all purposes while editing. Prores is out of the picture, sync issues were worse (several seconds of delay).

  For the record, the command used that didn’t work as expected (color wise) is :

  ffmpeg -channel_layout 63 -i input.mkv -map 0:0 -c:v dnxhd -vf "scale=in_range=limited:out_range=full" -color_range 2 -profile:v dnxhr_444 -pix_fmt yuv444p10le -acodec pcm_s24le -ar 48000 -ac 6 -channel_layout 63 -map 0:2 -hide_banner output.mxf

  I also tried without the commands "scale=in_range=limited:out_range=full" and "-color_range 2", with same results. Always used FFmpeg latest version, and I’m working in Windows 10 Pro, latest drivers and latest Klite codec pack. Video files were compared with Mediainfo, FFprobe, and visually with VLC.

  Well, like I said, I’m giving up using DNxHR as the source file for my project (it would have been ideal since it doesn’t have sync issues with the DNxHR proxies, and file size is not a problem for me). A user here at the forums suggested transcoding and use H.264 intra-frame as source file, which I didn’t know was an option (I didn’t know H.264 was capable of intra-frame, my bad). I’m aware that one should avoid unnecesary transcoding steps, but I can’t work with a H.264 UHD HDR source file (ultra slow playback), and the sync issues with proxies, no matter the codec, make it impossible to make accurate cuts.
  So, bottom line, I need to find a way to fix the color issue when transcoding to DNxHR, or try with an inter-frame codec that’s not DNxHR and that’s capable of preserving all the HDR info (and then see if it doesn’t have sync issues. I’m assuming that those may dissapear when using intra-frame for both source file and proxies).

  NOTE : When importing the DNxHR 444 file to Premiere Pro and looking at the Lumetri scopes tab, you can tell that the colors are clipped at 100 nits, like a regular SDR video. So apparently the color space was really reduced to BT709, and I don’t know why. The H.264 source file behaves as expected, with colors going past 100 nits.

  MY QUESTIONS :

  1) Is H.264 intra-frame a good format for editing with a good playback performance ?

  2) If H.264 intra-frame is a good option, what would be the advantages of the DNxHR codec (or Prores) over it for editing purposes ? Everybody suggests DNxHD/DNxHR or Prores as intermediate codecs, but if intra-frame H.264 has the same advantages for editing and supports HDR, what would be the reason to choose another codec like DNxHR ?

  3) Any ideas on what could be the cause of the colors not transcoding correctly from the H.264 source file to the DNxHR 444 10 bits one ? The command looks ok to me, but FFprobe output says the DNxHR video is BT709, while with the source file it says BT2020. Like I said, apparently there’s something wrong with the transcoding process regarding metadata or color space.

  4) I haven’t tried to transcode the source file to a DNxHR 444 10 bits video file, but in a MOV container. I don’t know how this works internally, but maybe the color issue has something to do with the container metadata or something. I may try this if there’s not another suggestion (transcoding this kind of files, as you know, takes time, so I’ll wait for some ideas first).

  NOTE : I tried to transcode the source file in the same way (DNxHR 444, 10 bits, etc) with Adobe Media Encoder 2020 and the result was the same, with colors messed up and FFprobe saying the video is BT709. Also tried transcoding to DNxHR HQX profile (10 bits), same result.

  Any help would be greatly appreciated.

  Thanks in advance.

• Anomalie #4128 (En cours) : Bug de génération de boucle avec les modèles Spip

  11 avril 2018, par Julien PORIAU

  Dans les modèles personnalisés Spip, les images (boucle documents ou logos) sont mal générées et provoque un bug d’encodage visible dans le front-end lors du passage dans une autre langue (balises multi).
  Nous n’avons pas trouvé où était le souci dans Spip, mais les caractères qui remontent dans le code source, ressemblent aux octets qui composent le fichier binaire d’une image.
  Voir en live ici : http://spip-dev.nidecker.com/probleme-de-langue.html?lang=ca.

  

  Pour essayer d’isoler cette anomalie, nous avons procédé de la sorte avec l’aide de mon développeur :

  1. Nous sommes reparti d’un SPIP 3.1.7 entièrement neuf (minimal), avec deux modèles Spip, rien d’autre.
  Le bug se reproduit, ce qui exclus un problème lié aux squelettes ou autres plugins.

  Nous n’avons pas réussi a déterminer précisément ce qui génère ce bug, à part que c’est dans un contexte où on appelle une langue pas définie dans le multi.
  En fonction du contenu de l’article, du nombre de modèles dans l’article, en fonction des boucles dans les inclure, le bug n’arrive pas au même endroit...

  Le problème vient de la génération des logos ou documents : si on supprime les balises #LOGO_* ou si on renomme IMG en IMG_, plus d’erreur.
  Même sans traitements, avec juste [(#LOGO_*)], rien à faire.

  2. Nous avons pensé que c’était peut être une image au mauvais format : On a alors tenté de passer ImageOptim sur tout le répertoire /IMG, redimensionné tous les logos en vignettes png de 320x240, rien à faire...

  3. On a fini par passer ce site de test en 3.2, pas mieux.

  4. Nous avons épluché les caches générés dans /tmp/cache et /tmp/cache/skel, tout paraît normal de ce côté là..

  5. On a ensuite un peu avancé en enlevant dans mes_options.php la variable $GLOBALS['forcer_lang'] = true".
  Sur la version minimal, plus de bug. Mais sur le site de production, le problème réside toujours.
  Mais en faisant des tests avec et sans (et en supprimant bien /tmp/cache/ à chaque fois), ça se confirme pour la version minimal.

  6. A partir d’une copie de la version production, nous avons désactivé tout les plugins, passer ImageOptim sur /IMG et rien a faire.. Impossible de déterminé d’où vient le problème :(

  7. Nous avons essayé d’écrire comme ceci : [<img src="http://core.spip.org/projects/spip/(#LOGO_MOT|image_reduire{50,*}|extraire_attribut{src})" alt="" style='max-width: 300px; max-height: 300px' />]
  Cela fonctionne sur la version minimal mais pas sur la version production.

  8. Dans la version minimal, j’ai encore récemment testé une dernière chose. J’ai supprimé les documents non sollicités sur ma page de teste (spip.php ?article1441&lang=ca).
  Avec la requête SQL suivante : DELETE FROM jones_documents WHERE id_document NOT IN (1948,1949,2534,2535,630,631,1783,1784,1785,1786,1787,1788,1781,1782)
  Le bug n’apparait plus..

  Je sèche..

  Vous trouverez ici en téléchargement une archive de la version minimal (Spip 3.1.7) : https://www.dropbox.com/s/dek0zg7jafl8uxe/jones.zip?dl=0] ( 20mo)
  Pour reproduire le bug, il suffit de passer la variable "&lang=ca" dans l’article 1441 (localhost/spip.php ?article1441&lang=ca).

  Je donne volontiers un accès à la version production si besoin.