Monday, June 2, 2025

2025-06-02- Filmer une scène cosplay en convention

Je fais un post rapide pour expliquer comment filmer une scene de concours cosplay en convention.

1 - Avoir une camera ou un appareil photo capable de filmer.

2 - Avoir un trépied ou un monopod. Le monopod va stabiliser, mais il se peut que vous bougiez un peu lateralement que vous l'utilisez. Le monopod à l'avantage de prendre moins de place.

3 - Se mettre à une ouverture donnée, au minimum f/6.4 ou f/8, le plus haut (en valeur de chiffre) que vous puissiez aller en montant en isos sans que la qualité ne se dégrade visuellement. Pour les puristes, on parle d'ouvrir quand le chiffre est bas, et de fermer quand il est haut.
Ex: F/8 800 isos sur un GH6 ça passe. A partir de 3200 isos, la qualité va se dégrader, donc on évitera de dépasser 1600 isos.
Les réglages peuvent varier selon votre modèle.

Le but est d'avoir une grande profondeur de champ et donc que les sujets présents sur votre scene soient nets.
Donc pas d'ouverture à F/1.4, F/1.7, F/2.8 ou f/4, vous avez besoin juste d'une optique qui soit correcte vers f/5.6 ou f/6.3 voire f/8.
Au dela, si vous avez des poussières sur le capteur, elles seront visibles, donc c'est à double tranchant d'aller trop haut en valeur et donc de trop fermer votre objectif.

4 - Faire la mise au point en avance, si votre vision est suffisante, vous pouvez y faire confiance et déterminer la zone de votre scène qui va être nette.
Sur le présentateur pendant la présentation ou avant que le concours ne commence. Puis, passez en mise au point manuelle.

Au niveau des réglages du 1080p est suffisant, les écrans 4k, pas beaucoup de monde en a, et il y a des chances que votre oeil ne fasse pas la différence.
Le 4k est bien pour recadrer, mais il multiplie par 10 les délais de traitement et ce, avant même de recadrer...


5 - Pour le cadrage, il faut que vous puissiez dézoomer totalement pour avoir la scène en entier. Si vous zoomer trop, il se peut que vous perdiez l'action. Vous pouvez essayer de suivre les participants, mais en restant en plan large, vous garantissez qu'on puisse généralement suivre l'action globale et comprendre.

6 - Déclencher la vidéo quand chaque participant arrive sur scène, couper à la fin de la prestation. Si vous avez un mode vidéo dédié, c'est souvent mieux.

Optionel - Si vous avez une bonne prise de son sur l'APN, vous aurez pas forcément besoin d'un micro externe. Le micro externe c'est un budget, le besoin essentiel est un retour vers les personnes passant sur scène, donc vous pouvez généralement vous en passer.
Avoir les audios venant de l'orga peut parfois aider, mais ça demande du boulot en post traitement et vous pouvez parfois multiplier par 5 les délais.

7 - Vérifier régulièrement que vous enregistrez au bon moment, couper pendant les interludes, en marche pendant le concours.

8 - Une fois que vous avez filmé, vous faites un backup dés que vous pouvez, comprendre dans un temps raisonnable.

9 - Vous faites un deuxieme backup avant de travailler sur vos vidéos, puis vous renommez vos vidéos en 01.mp4 02.mp4 03.mp4 .. 25.mp4 une par passage sur scène, vous comptez avant et aprés que vous en ayez pas effacer ou oublier une.

Si vous avez filmé en continu, il vous faudra couper par segment, mkvtoolnixgui peut gérer cela, maintenant je trouve que c'est plus compliqué de le gérer en post traitement.

9 - Pour traiter et couper les vidéos, j'utilise un script sous linux utilisant ffmpeg, il va créer des fichiers au format mp4 et prend du MP4 en entrée, au besoin vous adapter à votre environnement ou vous demandez à chatgpt de l'aide.
vous avez en commentaire la ligne de commande pour mkvmerge qui lui ne genérait que du mkv.
Le numéro est une partie pour identifier le nom du fichier (ex 01 ou 05 ) et le second paramètre le timing à la second pres; ex 3s
./cut.sh 01 5s si votre vidéos doit démarrer à 5 secondes.

Le script lance mpv sur le résultat final, comme ça vous vous pouvez vérifier le résultat rapidement.

Vous pouvez faire les opérations avec un autre logiciel, mais je trouve que c'est plus simple de régarder à quel moment il faut couper et de gérer chaque prestation en les coupant à la seconde prés.




#!/bin/bash

# $1 - parameter start
# $2 timing
base=$( pwd )
name="$(ls "$base/"*"$1"*.MP4)"
dest="/home/$USER/Vidéos" 

mkdir -p "$dest"

echo $(pwd)
echo name="$name"

if [ -z "$1" ]; then
  echo the script need one criterion to work
  echo possible criterions are:
  echo "$name" | sed 's|'$base'|\n|g' | sed 's|.MP4||g' 
  exit
fi

file=$( basename "$name" )
bfile=$( basename "$name" .MP4 )
t="$2"
if [ -z "$2" ]; then
  t="0s"
fi
echo cuting at t=$2

#"/usr/bin/mkvmerge" -o "$dest/$bfile.mkv"  "--forced-track" "0:no" "--forced-track" "1:no" "-a" "1" "-d" "0" "-S" "-T" "--no-global-tags" "--no-chapters" "(" "$base/$file" ")" "--track-order" "0:0,0:1" "--split" "timecodes:$t"

ffmpeg -i "$base/$file" -ss "$t" -c copy "$dest/$bfile.mp4"

ls -lart "$dest" 
mkdir -p "$base/mp4"
mv -v "$dest/$bfile.mp4" "$base/mp4"
df -h  "$dest" "$base"
mpv "$base/mp4/$bfile.mp4"
puis ensuite il ne reste qu'à les mettre en ligne sur youtube ou à les faire passer au personnes concernées.

Wednesday, May 28, 2025

2025-05-28- about the booking phase of cosplay conventions...

I'm making a blog entry here, once in a while.
I may be making another one in a relative future, I don't know yet, the other one will be about admission criterions and the way to select people for a cosplay convention.


Some people may have noticed, we might have a problem affecting most cosplay private cosplay conventions. Especially when it the event scales, over 100 persons in size, as people over the years tend to rush the booking phase, sometimes after admittance are announced and in 24 hours or 48 hours are fully booked for a lot of them or they pretend to be fully booked...

This can be explained by the Fear Of Missing Out phenomenon. It can also be explained by the possible lack of guidelines and regulations coming from the convention organizers.

I say possible lack because I only participated to a few events, well, that would 5 events now, it's more than a lots of people still, and I don't know the internal guidelines and regulations of all cosplay conventions. I have a list of events there.

I might have checked the rules of some, might have saved them for later analysis, but still, I'm far from being a specialist on the subject. Honestly, I also think nobody can pretend to have this kind of expertise as everyone might be thinking differently at some point.

Let's enter the subject: what is the problem? then, what should be done to prevent it?
The problem is that a lot of participants are rushing the booking phase, booking themselves and forcing other to book in fear.
Some participants are new, they'll be stressed and will panic over the fact they have to book with other people to make some shoot. The fear of missing will trigger some panic, some people will make them panic in saying they are booking with other people. Everyone wants to join the train and fear they will not catch it, so they add to the train and the panic and madness starts.

This means people who arrive late, because they are busy in real life or have no time to prepare this (eg: going to a convention on the weekend the results are announced, having a wedding, or another event), meaning they won't be there and people will get penalized if too many people book themselves in early phase, and that, sometimes months before the start of the event, for intance, Focus will happend by the end of september and we are in early june and some people were fully booked two days after the annoucement of participants... So four months before the event. Seriously there is still some margin...

There are also people coming from other countries and there might be accomodations, transports, sometimes visa and passport to take into account. Finally there are people who'd like to know who they can shoot with, who needs time to examinate the other people profile and decide who they might be shooting with. There are also some dialog between participants, and while answering lawfully (do not lie), clearly (yes / no / avoid using 'maybe') and shortly might help (not after three weeks the person asked), taking your time in doing that might probably help too.

Before what can be done to prevent that, a summary of the situation for some conventions:

We have two schools: the event who don't interfere at all and let the participants book together immediately for instance, to my knowledge: Volta or Focus.

Note: I am not going to list all the events because we have a lots of them and i don't know the inner of all...
Some people say it is fine, but they end up glued to phone and communication system for two days when this happends... I am not sure it is the best way...
Some other events seem to suggest a booking date and will ask participants to respect it: for instance, to my knowledge again, Pixelmania, Picvetia, Pulverisium, La Fortezza, sometimes the date is set quite shortly after the announcement of results but still, at least they communicate about it months before so people can prepare themselves psychologicaly, sometimes the booking phase can happend two or three months after admission, usually one or two months before the event starts. I'm fine as long you communicate before it and manage to respect it, issues can happend so there is probably some margin of appreciation here. Those organisers are non commercial entity, so I think we should respect them, even if we don't agree necessarily with them and even if there are other issues linked to those events. I am for having multiple events, so people can do along all those events and have a chance to participate.

We also don't know how the people will respect that delay when the convention ask them to wait. Some might be doing early or pre bookings, before the official booking phase, I'm fine with prebooking, as long people don't completely book themselves before the official date starts. It's understandable that you want to shoot with friends or people you want to absolutely shoot with. So if you book 30% to 50% of your planning in advance I think it is fine, some people books themselves by going slow volontary and its probably a good thing, you take your time, and shoot with who wants to shoot with you... you can also easily recognize that way people you care about you from the one who only see you in an utility way, not that the utility way is bad, but it should not take over the rest.

I think it is also good to always communicate lawfully, to do not to lie to other people, saying you're fully booked when you are just not interested in shooting with them.

So what can really done to help:

* Communicate on the timing before and respect it if you can, if you can't and are out of delay, communicate about it. Letting people who joined in the dark is not a good practice.
* Have a discord (or something similar) to synchronize the system, organize yourself and the participants privately, put there the informations they need: mandatory time (group photo, barbecue evening, opening of the HQ, retrieval of the badge...), you can also place the list of locations and the special events (horse / fire shootings etc.) there.
* Do not publish the list of participants immediately. I think it should be done before, at least one week before the booking phase. I feel that one week is really short, but two weeks could help. If you intend to have a phase where people might cancel their participation, you could set more time so you can set people to remplace the people who will not join and let them participate without penalizing them by joining after the booking phase. If you do another roll, you should indicate if the booking phase started or not. I am not interested myself in joining an even if the booking phase started, newscomer might be interested, but they should know it's a degraded experience.
* If you are using a discord system, separate your populations and let them prepare their own threads on separate sections the other populations can't access, do not publish announcement of people who are joining on the social networks. Ask your third parties provider to respect the official delays, you can't say people have to wait while fire masters or horse providers say the booking are their side are opening and are throing people in panic mode...
* Publish before and during the event guidelines explaining how one should proceed, like deciding a number of shooting slots per day, which costume they'll wear if they are a model and how they'll participate. Link them resources.
* While we are in the suggestion part to organizer, do full days if you can and open your HQ the day before the convention starts, so technical and administrative tasks can be done before the event. A friday starting at 14h00 means you lose a lot of possible shooting time in the morning. Your rules and regulation should not apply to public places before the event starts.
* Always reminds your participants of the laws and local interdictions.

* Communicate with the other events so you don't open applications on the same day...

If you are a participant:
* Delay yourself a bit, take your time, look at the profiles, do not immediately book, if you want to favor some people it's fine, but don't wait too much for them.
* Communicate lawfully, you can communicate with several participant at the time by reducting the days you'll shoot with. I'm ok with a first arrived first served system.
* Beware of deadlocks: participant A wants to shoot with B who wants to shoot with C who wants to with D who wants to shoot with A... everyone ends deadlocked because they wait for another participant and there is a loop.
* Always take into account the fact you'll have to change place and it might takes some time.
* Please think before the event of what you wish to do, your planning, and how many shootings you want to do per day. Models can be limited due the fact posing and wearing a costume will worn them out. 2-6 shoots per day can be fine for a model, a photographer who stays at the same spot could do 8-10 shoots a day, now I'm limiting to 5-6 per day most of the time. Some photographers will do 4 shootings a day, I've seen one doing two shootings at a day and i think it was fine. Most models will do 3-5 shootings, sometimes only 2.
* Plan your days into either an excel sheet or textfile. I use textfile since i prefers them, but any system will work. I hide participants names and details but my planning will show if I am free or booked at a given time. You can publish it or link them to other people, so people will know if you are free or booked at which time without asking you.
* Organization tips: i usually use a three state system for my plannings:
free: the slot if free and can be booked.
locked: the slot is locked and is waiting for some details to it can be confirmed.
shoot: the shoot will take place unless some major issue is arriving.
you can also indicate your other activities: pause / eating / move to a place etc.
Always keep a margin of security if you can. If the slot duration is one hour, plan in doing the shoot in 15-30 minutes if the person is late or having issue. If it's more in duration, you can plan your shooting time accordingly.
* Communicate if you have an issue, especially during the event, do not let other people in the dark.
* Respect the timings, do not go over schedule or you'll penalize your model for the other shootings and others photographers. Sadly this is important. If you have empty slots, you can convert them in unscheduled shootings or pause, depending your condition during the event.
* Respect you engagements. If you agreed to shoot with someone do not cancel it to shoot with someone else.
* Avoid going on the "hypocrisy path" by saying something and going another way, participants will talk to each others and will know if you do such practices, this will always end in reducting your trust to others.
* a general rule: if you think something may create an issue, don't do it, it's true from the instant you might this is will create an issue.
* respect the convention guidelines.
* have fun.

Those are suggestions, you are free to use them or share them, if your are an organizer you are free to incorporate them in your guidelines or regulations, depending how you feel it.
As organizers, you could try asking your participants if they have issues during all phases, if you can see there is or will be a lack of photographers or models, you could organize another round of applications, with a short process so you admit them before the booking starts.
A final note about the parity between models and photographers in such event: models tends to shoot less than photographers,if you want people to organize duo or trios, you might also take that in your ratio, since they might be 2 or 3 models to shoot with one photographer, so you might want less photographers than models in your event. something like 55, 60 or 70 models per 50 photographers. You could also ask prior the booking phase how many shootings a photographer will do and how many shootings a model wants to do, and indicate this is not a criterion to join the event and calculate if this could work not not.