Video playback with renderer accelleration fails (works fine with SW)

SDL Development
1

Hello everyone,

First of all apologies if this has been asked before, but I honestly couldn’t find it.
So here’s my problem, I’m trying to create a simple video/stream player using SDL2.
I’m using gstreamer to get the stream from an RTSP/H264 source.

I managed to get it working when I create the renderer with SDL_RENDERER_SOFTWARE flag on, but if I leave it empty (or set SDL_RENDERER_ACCELERATED) to get HW accelleration, nothing is displayed.
I’m sure I’m missing something very fundamental, but being a newbie in SDL2 world I can’t put my finger on it.

Here’s the source code:
http://tpcg.io/_3MENV0
(not sure what the common practice here is for sharing code)

The non-working output of the above code is:

** (process:35303): DEBUG: 18:09:08.819: Detected display 0: 1920 x 1080
** (process:35303): DEBUG: 18:09:08.844: Driver 0 : opengl
** (process:35303): DEBUG: 18:09:08.844: Driver 1 : opengles2
** (process:35303): DEBUG: 18:09:08.844: Driver 2 : software
** (process:35303): DEBUG: 18:09:08.844: Current video driver: x11
** (process:35303): DEBUG: 18:09:08.844: Rendering driver: opengl
** (process:35303): DEBUG: 18:09:08.846: Starting pipeline
** (process:35303): DEBUG: 18:09:08.846: GST init
** (rtspplayer:35303): DEBUG: 18:09:08.857: GST Parse launch
** (rtspplayer:35303): DEBUG: 18:09:08.894: GST Setting frame callback (0x648abef3cc10)
** (rtspplayer:35303): DEBUG: 18:09:08.894: GST Set to ready
** (rtspplayer:35303): DEBUG: 18:09:08.894: GST Set to playing
** (rtspplayer:35303): DEBUG: 18:09:08.894: Pipeline playing
** (rtspplayer:35303): DEBUG: 18:09:18.202: Rendered!
** (rtspplayer:35303): DEBUG: 18:09:18.242: Rendered!
** (rtspplayer:35303): DEBUG: 18:09:18.283: Rendered!
** (rtspplayer:35303): DEBUG: 18:09:18.325: Rendered!
** (rtspplayer:35303): DEBUG: 18:09:18.365: Rendered!
...
...

Some additional info:
glxinfo shows “direct rendering: Yes”
Running on Ubuntu 23.04 and Intel CPU and integrated GPU with, supposedly, all proper GPU drivers installed.

The same way, when trying to use the wayland driver I get the same behavior (nothing plays)

Thank you very much!

2

You call SDL_UpdateTexture() which is documented as “a fairly slow function, intended for use with static textures that do not change often” which doesn’t seem to fit a video playback application at all!

I would suggest you create your videoTexture as SDL_TEXTUREACCESS_STREAMING then update it using SDL_LockTexture() and SDL_UnlockTexture().

2 Likes
3

You can look at testffmpeg.c to see how to do hardware accelerated video playback on SDL3.

2 Likes
4

Thank you both for your tips.
I tried using SDL_LockTexture/SDL_UnlockTexture but I’m getting a greenish picture, most likely because of the pixel format used (YUV).
Actually, if I look at the example suggested by slouken, the YUV texture is using SDL_UpdateYUVTexture not lock/unlock.

In any case, the inital issue I was having (can’t get it to work with HW accelleration enabled) seems to persist.

5

It works OK for me. Are you definitely creating your texture with the correct pixel format? This is what I use:

  tex = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_UYVY, SDL_TEXTUREACCESS_STREAMING, XLEN, YLEN);

Then I render the frames like this (in my case reading directly from a video file to the texture to avoid any wasteful copy operations):

  SDL_LockTexture(tex, NULL, &pixels, &pitch);
  SDL_RWread(file, pixels, size, 1);
  SDL_UnlockTexture(tex);
  SDL_RenderCopy(renderer, tex, NULL, &dst);

This works fine with an accelerated renderer here, but I should emphasise that I’m using OpenGL (even in Windows), not Direct3D.

You can run my code here to prove it really works!

1 Like
6

Once again, thank you for the pointers.
I managed to get all 3 methods working fine (SDL_UpdateTexture, SDL_UpdateYUVTexture and SDL_LockTexture/SDL_UnlockTexture). Video plays nicely.

What I still couldn’t get working was the HW accelleration.
Whenever I set the renderer flag to SDL_RENDERER_ACCELERATED I get nothing on the screen (black), although the code processing each frame seems to be working fine.
Any ideas here are much appreciated.