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• Creating an ffmpeg html/php form process and need ffmpeg technical feedback

  7 juin 2016, par dave

  I have decided to create an input form for ffmpeg to go with my video uploader.

  This is for my video uploader plugin for a social site software. Users have told me that they want technical options for videos so they can choose the specific options they want including thumbnail options.

  I have been reading the ffmpeg docs most of the morning as well as watching some videos and i have come up with a rough draft of my form. The videos uploaded will more than likely be non gaming, personal and hobby videos.

  The goal here is to have a form that is easy enough for the non technical user, but technical for those that want the options. So i do plan to have a checkbox which allows the non technical user to skip the technical settings. This will result in a generic ffmpeg command with default settings. If they choose to use the technical specs then it will create a more specific ffmpeg command stream.

  here is what i have so far in the draft.

  select max size options ’50MB’,’100MB’,’200MB’,’500MB’,’650MB’,’750MB’,’1GB’,’2GB’,’3GB’

  input for thumbcapture in seconds maxlength 2 size 2

  input for video in ’mpg’,’wma’,’mov’,’flv’,’mp4’,’avi’,’qt’,’wmv’,’rm’

  option for video size ’200x100’,’320x240’,’560x315’,’640x360’,’853x480’,’1280x720’ not sure if i want to offer a custom slot or not.

  my thought here is that if they do not want the tech version of the form then the codecs will be b:v copy b:a copy (if that is the smart way to do it) or just left out and let ffmpeg decide what is best.

  ===== this is the technical part of the form =======

  select for acodec options copy, mp3, mp1, mp2, dnet, 28_8, wmav2, alac, cook

  select for vcodec option copy, ffv1, ms-cram, mpeg-4, rv40, wmv, xvid, mov, qt, avchd

  select for bitrate audio 32k, 64k, 128k

  select for bitrate video 1000k, 1200k, 1500k

  select for sampling rate 22050, 44100

  input for crf(mp4 out only) size 2 maxlength 2 minval 2 maxval 49

  input for avi quantanizer (avi out only) size 2 maxlength 2 minval 2 maxval 49

  ===== end technical form =====================

  select for video out ’avi’,’mp4’,’flv’

  that is what i have so far. How does that combination on the technical side look to you ffmpeg pros ?

  Any suggestions ? :)

• Back porting ffmpeg.dll from electron for windows xp by disassembling

  28 juillet 2024, par Oosuke Ren

  I've recently gotten into a really interesting project of having a fully functional (and as futuristic as possible) physical retro gaming machine with windows xp. I had found One Core Api that successfully works to allow for some programs to work that otherwise wouldn't have. One of them is electron (5.0.13). Thanks to a vast testing between a VM with the kernel extender and a vanilla XP, I found out that the only thing stopping me from succeeding is because it's dependent on an EXTREMELY specific version/fork of ffmpeg (Chromium fork of ffmpeg 4.1) . Due to that being a relatively old fork/version, the build tools/links for some of the stuff are nonexistent right now, so even if I do have the fork locally with all the instructions, I can't build it. (and if I do I have to patch Win Vista+ Api functions, with one custom stub dll I have)

  


  AcquireSRWLockExclusive InitializeConditionVariable SleepConditionVariableSRW InitOnceBeginInitialize InitOnceComplete InitializeSRWLock ReleaseSRWLockExclusive WakeAllConditionVariable WakeConditionVariable

  


  Since I can't custom build ffmpeg I have to patch it's calls by redirecting them to my custom dll that includes these back ported functions and more.

  


  I tried many different ways => IDA Pro, Ghidra, objconv, currently am the closest with "DLL to C"

  


  Ida Pro and Ghidra seem to not be creating assembly code that I'd be able to assemble back after patching.

  


  objconv produces a really accurate disassembly, but the issue is it doesn't have an assembler. And the produced .asm won't assemble with Fasm, masm or nasm

  


  As for DLL to C-> successfully created a quite presentable VS project, the project successfully compiles with only one warning, the byte sizes is quite similar, the problem is => the functions are getting wrongly directed (towards wrong functions in my dll- and thus the ones needed are undefined) And this is too deep to be able to tell if it's a VS version issue, wrong code implementation or if just DLL to C has wrongly disassembled the logic.

  


  Question is, is my last option remaining to manually edit the HEXES of the Import Address Table and Import Names so they get redirected ? (the problem is my knowledge in Assembly isn't too good, so I'm not sure if that's all I'd have to do, and even if so, I have a feeling I'd mess up the Virtual Addresses or something.

  


• Efficient way to stream a sequence of frames

  3 juin 2020, par DoriHp 0

  I'm facing with an issue : I implemented a device to detect stranger for my home, which includes inputs from some IP camera and use a tensorflow model to process frame got from them.

  



  Now I want to build a dashboard (use Flask or Django - python framework as backend) to streaming the processed frames I got from the system, and if possible, do some transform on them (such as stack multi frames into one, etc), and run the server so I can watch it from distances. Currently, I'm sending frame by frame as independent images but it costs so much bandwidth. I read how h264 encoder work and felt very exicted about it. Now, the question is, how can I use h264 or any encoder like it transfer my data and reduce the bandwidth ?