[libcamera-devel] [PATCH v8 4/4] cam: sdl_sink: Add MJPG support to SDL sink

[Kieran Bingham]

Quoting Eric Curtin via libcamera-devel (2022-05-05 16:18:51)
> So we have at least two supported capturing pixel formats (although
> many possible output pixel formats thanks to SDL conversion). MJPG
> support only built in if SDL2_image is available, provides
> decompression.
> 
> Signed-off-by: Eric Curtin <ecurtin at redhat.com>
> ---
>  src/cam/meson.build          |  9 +++++++++
>  src/cam/sdl_sink.cpp         |  9 +++++++++
>  src/cam/sdl_texture_mjpg.cpp | 18 ++++++++++++++++++
>  src/cam/sdl_texture_mjpg.h   | 10 ++++++++++
>  4 files changed, 46 insertions(+)
>  create mode 100644 src/cam/sdl_texture_mjpg.cpp
>  create mode 100644 src/cam/sdl_texture_mjpg.h
> 
> diff --git a/src/cam/meson.build b/src/cam/meson.build
> index 3032730b..afc0ea9f 100644
> --- a/src/cam/meson.build
> +++ b/src/cam/meson.build
> @@ -41,6 +41,14 @@ if libsdl2.found()
>          'sdl_texture.cpp',
>          'sdl_texture_yuyv.cpp'
>      ])
> +
> +    libsdl2_image = dependency('SDL2_image', required : false)
> +    if libsdl2.found()
> +        cam_cpp_args += ['-DHAVE_SDL_IMAGE']
> +        cam_sources += files([
> +            'sdl_texture_mjpg.cpp'
> +        ])
> +    endif
>  endif

All this extending complexity that is sdl specific makes me wish more
that this was under src/cam/sdl/ with a dedicated meson.build there, but
that could also be done on top.

This looks quite straightforward so far so:


Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

>  
>  cam  = executable('cam', cam_sources,
> @@ -49,6 +57,7 @@ cam  = executable('cam', cam_sources,
>                        libcamera_public,
>                        libdrm,
>                        libsdl2,
> +                      libsdl2_image,
>                        libevent,
>                    ],
>                    cpp_args : cam_cpp_args,
> diff --git a/src/cam/sdl_sink.cpp b/src/cam/sdl_sink.cpp
> index 6fbeaf56..f15c01cb 100644
> --- a/src/cam/sdl_sink.cpp
> +++ b/src/cam/sdl_sink.cpp
> @@ -19,6 +19,10 @@
>  
>  #include "sdl_texture_yuyv.h"
>  
> +#ifdef HAVE_SDL_IMAGE
> +#include "sdl_texture_mjpg.h"
> +#endif
> +
>  #include "event_loop.h"
>  #include "image.h"
>  
> @@ -59,6 +63,11 @@ int SDLSink::configure(const libcamera::CameraConfiguration &config)
>         case libcamera::formats::YUYV:
>                 sdlTexture_ = std::make_unique<SDLTextureYUYV>(sdlRect_);
>                 break;
> +#ifdef HAVE_SDL_IMAGE
> +       case libcamera::formats::MJPEG:
> +               sdlTexture_ = std::make_unique<SDLTextureMJPG>(sdlRect_);
> +               break;
> +#endif
>         default:
>                 std::cerr << "Unsupported pixel format "
>                           << cfg.pixelFormat.toString() << std::endl;
> diff --git a/src/cam/sdl_texture_mjpg.cpp b/src/cam/sdl_texture_mjpg.cpp
> new file mode 100644
> index 00000000..636fdbea
> --- /dev/null
> +++ b/src/cam/sdl_texture_mjpg.cpp
> @@ -0,0 +1,18 @@
> +#include "sdl_texture_mjpg.h"
> +
> +#include <SDL2/SDL_image.h>
> +
> +using namespace libcamera;
> +
> +SDLTextureMJPG::SDLTextureMJPG(const SDL_Rect &sdlRect)
> +       : SDLTexture(sdlRect, SDL_PIXELFORMAT_RGB24, 0)
> +{
> +}
> +
> +void SDLTextureMJPG::update(const Span<uint8_t> &data)
> +{
> +       SDL_RWops *buffer_stream = SDL_RWFromMem(data.data(), data.size());
> +       SDL_Surface *frame = IMG_Load_RW(buffer_stream, 0);
> +       SDL_UpdateTexture(ptr_, NULL, frame->pixels, frame->pitch);
> +       SDL_FreeSurface(frame);
> +}
> diff --git a/src/cam/sdl_texture_mjpg.h b/src/cam/sdl_texture_mjpg.h
> new file mode 100644
> index 00000000..fefaaeeb
> --- /dev/null
> +++ b/src/cam/sdl_texture_mjpg.h
> @@ -0,0 +1,10 @@
> +#pragma once
> +
> +#include "sdl_texture.h"
> +
> +class SDLTextureMJPG : public SDLTexture
> +{
> +public:
> +       SDLTextureMJPG(const SDL_Rect &sdlRect);
> +       void update(const libcamera::Span<uint8_t> &data) override;
> +};
> -- 
> 2.35.1
>