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Rennes Emotion Map 2010-11
19 octobre 2011, par
Mis à jour : Juillet 2013
Langue : français
Type : Texte
Autres articles (50)
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Les autorisations surchargées par les plugins
27 avril 2010, parMediaspip core
autoriser_auteur_modifier() afin que les visiteurs soient capables de modifier leurs informations sur la page d’auteurs -
Support audio et vidéo HTML5
10 avril 2011MediaSPIP utilise les balises HTML5 video et audio pour la lecture de documents multimedia en profitant des dernières innovations du W3C supportées par les navigateurs modernes.
Pour les navigateurs plus anciens, le lecteur flash Flowplayer est utilisé.
Le lecteur HTML5 utilisé a été spécifiquement créé pour MediaSPIP : il est complètement modifiable graphiquement pour correspondre à un thème choisi.
Ces technologies permettent de distribuer vidéo et son à la fois sur des ordinateurs conventionnels (...) -
De l’upload à la vidéo finale [version standalone]
31 janvier 2010, parLe chemin d’un document audio ou vidéo dans SPIPMotion est divisé en trois étapes distinctes.
Upload et récupération d’informations de la vidéo source
Dans un premier temps, il est nécessaire de créer un article SPIP et de lui joindre le document vidéo "source".
Au moment où ce document est joint à l’article, deux actions supplémentaires au comportement normal sont exécutées : La récupération des informations techniques des flux audio et video du fichier ; La génération d’une vignette : extraction d’une (...)
Sur d’autres sites (8710)
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flutter_ffmpeg is discontinued with no alternatives ?
13 mars, par Rageh AzzazyBased on this article by Taner Sener
https://tanersener.medium.com/saying-goodbye-to-ffmpegkit-33ae939767e1


and after the discontinuation of flutter_ffmpeg and ffmpeg_kit_flutter packages.


most packages for executing video editing commands were built depending on them and so won't work After April 1, 2025 as mentioned in the package documentation and Taner's article.


example of packages depending on flutter_ffmpeg or ffmpeg_kit_flutter like


- 

- video_trimmer
- zero_video_trimmer
- flutter_video_trimmer
- video_trim
- bemeli_compress
- video_trimmer_pro
- ... others
















and editing video using video_editor or video_editor_2 or video_editor_pits has become a problem


and I believe downloading the binaries and doing the whole thing locally is not just tedious but illegal as well.


so I broke down exactly what I need to edit videos in my flutter app


and I found those package but not yet tested them


Trimming : flutter_native_video_trimmer


Compression : video_compress or video_compress_plus


Muting : video_compress handles this


Encoding : Not sure, I just need a simple MP4 video files


Cropping : I can't find a solution for video cropping


I don't need to rotate, reverse or do any fancy stuff to the videos, just those five functions.


so now only remaining solution for this approach is to find a simple video cropping function and an encoder that work on flutter IOS & Android


so my question is not looking for external library recommendation but
do you have any ideas how to crop a video in flutter natively ?


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How does FFmpeg determine the “attached pic” and “timed thumbnails” dispositions of an MP4 track ?
6 mars, par obskyrThe Issue


FFmpeg has a concept of “dispositions” – a property that describes the purpose of a stream in a media file. For example, here are the streams in a file I have lying around, with the dispositions emphasized :


Stream #0:0[0x1](und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo,
fltp, 251 kb/s <strong><em>(default)</em></strong>
 Metadata:
 creation_time : 2021-11-10T20:14:06.000000Z
 handler_name : Core Media Audio
 vendor_id : [0][0][0][0]

 Stream #0:1[0x2](und): Video: mjpeg (Baseline) (jpeg / 0x6765706A),
yuvj420p(pc, bt470bg/unknown/unknown), 1024x1024, 0 kb/s, 0.0006 fps, 3.08 tbr,
600 tbn <strong><em>(default) (attached pic) (timed thumbnails)</em></strong>
 Metadata:
 creation_time : 2021-11-10T20:14:06.000000Z
 handler_name : Core Media Video
 vendor_id : [0][0][0][0]

 Stream #0:2[0x3](und): Data: bin_data (text / 0x74786574)
 Metadata:
 creation_time : 2021-11-10T20:14:06.000000Z
 handler_name : Core Media Text

 Stream #0:3[0x0]: Video: mjpeg (Baseline), yuvj420p(pc, bt470bg/unknown/
unknown), 1024x1024 [SAR 144:144 DAR 1:1], 90k tbr, 90k tbn <strong><em>(attached pic)</em></strong>

However, if I make any modification to this file’s chapter markers using the C++ library MP4v2 (even just re-saving the existing ones :
auto f = MP4Modify("test.m4a"); MP4Chapter_t* chapterList; uint32_t chapterCount; MP4GetChapters(f, &chapterList, &chapterCount); MP4SetChapters(f, chapterList, chapterCount); MP4Close(f);), some of these dispositions are removed :

Stream #0:0[0x1](und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo,
fltp, 251 kb/s <strong><em>(default)</em></strong>
 Metadata:
 creation_time : 2021-11-10T20:14:06.000000Z
 handler_name : Core Media Audio
 vendor_id : [0][0][0][0]

 Stream #0:1[0x2](und): Video: mjpeg (Baseline) (jpeg / 0x6765706A),
yuvj420p(pc, bt470bg/unknown/unknown), 1024x1024, 0 kb/s, 0.0006 fps, 3.08 tbr,
600 tbn <strong><em>(default)</em></strong> <kbd>← “attached pic” and “timed thumbnails” removed!</kbd>
 Metadata:
 creation_time : 2021-11-10T20:14:06.000000Z
 handler_name : Core Media Video
 vendor_id : [0][0][0][0]

 Stream #0:2[0x0]: Video: mjpeg (Baseline), yuvj420p(pc, bt470bg/unknown/
unknown), 1024x1024 [SAR 144:144 DAR 1:1], 90k tbr, 90k tbn <strong><em>(attached pic)</em></strong>

 Stream #0:3[0x4](und): Data: bin_data (text / 0x74786574)
 <kbd>This stream was moved to the end, but that’s intended behavior. It contains chapter titles, and we just edited the chapters.</kbd>
 Metadata:
 creation_time : 2025-03-05T09:56:31.000000Z

It also renders the file unplayable in MPC-HC (but not in VLC !), which is apparently a bug in MP4v2. I’m currently investigating that bug to report and potentially fix it, but that’s a separate issue – in my journey there, I’m wracking my brain trying to understand what it is that MP4v2 changes to make FFmpeg stop reporting the “attached pic” and “timed thumbnails” dispositions. I’ve explored the before-and-afters in MP4 Box, and I can’t for the life of me find which atom it is that differs in a relevant way.


(I’d love to share the files, but unfortunately the contents are under copyright – if anyone knows of a way to remove the audio from an MP4 file without changing anything else, let me know and I’ll upload dummied-out versions. Without them, I can’t really ask about the issue directly. I can at least show you the files’ respective atom trees, but I’m not sure how relevant that is.)


The Question


I thought I’d read FFmpeg’s source code to find out how it determines dispositions for MP4 streams, but of course, FFmpeg is very complex. Could someone who’s more familiar with C and/or FFmpeg’s codebase help me sleuth out how FFmpeg determines dispositions for MP4 files (in particular, “attached pic” and “timed thumbnails”) ?


Some Thoughts…


- 

- I figure searching for “attached_pic” might be a good start ?
- Could the MP4 muxer
movenc.cbe helpful ? - I’d imagine what we’d really like to look at is the MP4 demuxing process, as it’s during demuxing that FFmpeg determines dispositions from the data in the file. After poring over the code for hours, however, I’ve been utterly unable to find where that happens.








-
How does FFmpeg determine the dispositions of an MP4 track ?
5 mars, par obskyrThe Issue


FFmpeg has a concept of “dispositions” – a property that describes the purpose of a stream in a media file. For example, here are the streams in a file I have lying around, with the dispositions emphasized :


Stream #0:0[0x1](und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo,
fltp, 251 kb/s <strong><em>(default)</em></strong>
 Metadata:
 creation_time : 2021-11-10T20:14:06.000000Z
 handler_name : Core Media Audio
 vendor_id : [0][0][0][0]

 Stream #0:1[0x2](und): Video: mjpeg (Baseline) (jpeg / 0x6765706A),
yuvj420p(pc, bt470bg/unknown/unknown), 1024x1024, 0 kb/s, 0.0006 fps, 3.08 tbr,
600 tbn <strong><em>(default) (attached pic) (timed thumbnails)</em></strong>
 Metadata:
 creation_time : 2021-11-10T20:14:06.000000Z
 handler_name : Core Media Video
 vendor_id : [0][0][0][0]

 Stream #0:2[0x3](und): Data: bin_data (text / 0x74786574)
 Metadata:
 creation_time : 2021-11-10T20:14:06.000000Z
 handler_name : Core Media Text

 Stream #0:3[0x0]: Video: mjpeg (Baseline), yuvj420p(pc, bt470bg/unknown/
unknown), 1024x1024 [SAR 144:144 DAR 1:1], 90k tbr, 90k tbn <strong><em>(attached pic)</em></strong>

However, if I make any modification to this file’s chapter markers using the C++ library MP4v2 (even just re-saving the existing ones :
auto f = MP4Modify("test.m4a"); MP4Chapter_t* chapterList; uint32_t chapterCount; MP4GetChapters(f, &chapterList, &chapterCount); MP4SetChapters(f, chapterList, chapterCount); MP4Close(f);), some of these dispositions are removed :

Stream #0:0[0x1](und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo,
fltp, 251 kb/s <strong><em>(default)</em></strong>
 Metadata:
 creation_time : 2021-11-10T20:14:06.000000Z
 handler_name : Core Media Audio
 vendor_id : [0][0][0][0]

 Stream #0:1[0x2](und): Video: mjpeg (Baseline) (jpeg / 0x6765706A),
yuvj420p(pc, bt470bg/unknown/unknown), 1024x1024, 0 kb/s, 0.0006 fps, 3.08 tbr,
600 tbn <strong><em>(default)</em></strong> <kbd>← “attached pic” and “timed thumbnails” removed!</kbd>
 Metadata:
 creation_time : 2021-11-10T20:14:06.000000Z
 handler_name : Core Media Video
 vendor_id : [0][0][0][0]

 Stream #0:2[0x0]: Video: mjpeg (Baseline), yuvj420p(pc, bt470bg/unknown/
unknown), 1024x1024 [SAR 144:144 DAR 1:1], 90k tbr, 90k tbn <strong><em>(attached pic)</em></strong>

 Stream #0:3[0x4](und): Data: bin_data (text / 0x74786574)
 <kbd>This stream was moved to the end, but that’s intended behavior. It contains chapter titles, and we just edited the chapters.</kbd>
 Metadata:
 creation_time : 2025-03-05T09:56:31.000000Z

It also renders the file unplayable in MPC-HC (but not in VLC !), which is apparently a bug in MP4v2. I’m currently investigating that bug to report and potentially fix it, but that’s a separate issue – in my journey there, I’m wracking my brain trying to understand what it is that MP4v2 changes to make FFmpeg stop reporting the “attached pic” and “timed thumbnails” dispositions. I’ve explored the before-and-afters in MP4 Box, and I can’t for the life of me find which atom it is that differs in a relevant way.


(I’d love to share the files, but unfortunately the contents are under copyright – if anyone knows of a way to remove the audio from an MP4 file without changing anything else, let me know and I’ll upload dummied-out versions. Without them, I can’t really ask about the issue directly. I can at least show you the files’ respective atom trees, but I’m not sure how relevant that is.)


The Question


I thought I’d read FFmpeg’s source code to find out how it determines dispositions for MP4 streams, but of course, FFmpeg is very complex. Could someone who’s more familiar with C and/or FFmpeg’s codebase help me sleuth out how FFmpeg determines dispositions for MP4 files (in particular, “attached pic” and “timed thumbnails”) ?


Some Thoughts…


- 

- I figure searching for “attached_pic” might be a good start ?
- Could the MP4 muxer
movenc.cbe helpful ? - I’d imagine what we’d really like to look at is the MP4 demuxing process, as it’s during demuxing that FFmpeg determines dispositions from the data in the file. After poring over the code for hours, however, I’ve been utterly unable to find where that happens.








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