[libcamera-devel] [PATCH v7 2/2] cam: sdl_sink: Add SDL sink
Eric Curtin
ecurtin at redhat.com
Tue Apr 19 16:47:17 CEST 2022
On Fri, 15 Apr 2022 at 18:13, Laurent Pinchart
<laurent.pinchart at ideasonboard.com> wrote:
>
> Hi Eric,
>
> Thank you for the patch.
>
> On Fri, Apr 08, 2022 at 05:00:15PM +0100, Eric Curtin via libcamera-devel wrote:
> > This adds more portability to existing cam sinks. You can pass a
> > YUYV camera buffer for example and SDL will handle the pixel buffer
> > conversion, although SDL does not support decompression for pixelformats
> > like MJPEG. This allows cam reference implementation to display images
> > on VMs, Mac M1, Raspberry Pi, etc. This also enables cam reference
> > implementation, to run as a desktop application in wayland or x11.
> > SDL also has support for Android and ChromeOS which has not been tested.
> > Also tested on simpledrm raspberry pi 4 framebuffer successfully where
> > existing kms sink did not work. Can also be used as kmsdrm sink. Only
> > supports one camera stream at present.
> >
> > Signed-off-by: Eric Curtin <ecurtin at redhat.com>
> > ---
> > src/cam/camera_session.cpp | 8 ++
> > src/cam/main.cpp | 5 +
> > src/cam/main.h | 1 +
> > src/cam/meson.build | 10 ++
> > src/cam/sdl_sink.cpp | 198 +++++++++++++++++++++++++++++++++++++
> > src/cam/sdl_sink.h | 46 +++++++++
> > 6 files changed, 268 insertions(+)
> > create mode 100644 src/cam/sdl_sink.cpp
> > create mode 100644 src/cam/sdl_sink.h
> >
> > diff --git a/src/cam/camera_session.cpp b/src/cam/camera_session.cpp
> > index 0428b538..30162dbd 100644
> > --- a/src/cam/camera_session.cpp
> > +++ b/src/cam/camera_session.cpp
> > @@ -19,6 +19,9 @@
> > #ifdef HAVE_KMS
> > #include "kms_sink.h"
> > #endif
> > +#ifdef HAVE_SDL
> > +#include "sdl_sink.h"
> > +#endif
> > #include "main.h"
> > #include "stream_options.h"
> >
> > @@ -187,6 +190,11 @@ int CameraSession::start()
> > sink_ = std::make_unique<KMSSink>(options_[OptDisplay].toString());
>
> Space before tab. There are several occurrences.
>
> > #endif
> >
> > +#ifdef HAVE_SDL
> > + if (options_.isSet(OptSDL))
> > + sink_ = std::make_unique<SDLSink>();
> > +#endif
> > +
> > if (options_.isSet(OptFile)) {
> > if (!options_[OptFile].toString().empty())
> > sink_ = std::make_unique<FileSink>(streamNames_,
> > diff --git a/src/cam/main.cpp b/src/cam/main.cpp
> > index c7f664b9..1d62a64a 100644
> > --- a/src/cam/main.cpp
> > +++ b/src/cam/main.cpp
> > @@ -137,6 +137,11 @@ int CamApp::parseOptions(int argc, char *argv[])
> > "Display viewfinder through DRM/KMS on specified connector",
> > "display", ArgumentOptional, "connector", false,
> > OptCamera);
> > +#endif
> > +#ifdef HAVE_SDL
> > + parser.addOption(OptSDL, OptionNone,
> > + "Display viewfinder through SDL",
> > + "sdl", ArgumentNone, "", false, OptCamera);
>
> I'm tempted to refactor the -D option to specify the backend as an
> argument, given that the KMS and SDL sinks are mutually exclusive. I
> think this can be done later though.
>
> > #endif
> > parser.addOption(OptFile, OptionString,
> > "Write captured frames to disk\n"
> > diff --git a/src/cam/main.h b/src/cam/main.h
> > index 62f7bbc9..2b285808 100644
> > --- a/src/cam/main.h
> > +++ b/src/cam/main.h
> > @@ -18,6 +18,7 @@ enum {
> > OptListProperties = 'p',
> > OptMonitor = 'm',
> > OptStream = 's',
> > + OptSDL = 'S',
> > OptListControls = 256,
> > OptStrictFormats = 257,
> > OptMetadata = 258,
> > diff --git a/src/cam/meson.build b/src/cam/meson.build
> > index 5bab8c9e..59787741 100644
> > --- a/src/cam/meson.build
> > +++ b/src/cam/meson.build
> > @@ -32,11 +32,21 @@ if libdrm.found()
> > ])
> > endif
> >
> > +libsdl2 = dependency('SDL2', required : false)
> > +
> > +if libsdl2.found()
> > + cam_cpp_args += ['-DHAVE_SDL']
> > + cam_sources += files([
> > + 'sdl_sink.cpp'
> > + ])
> > +endif
> > +
> > cam = executable('cam', cam_sources,
> > dependencies : [
> > libatomic,
> > libcamera_public,
> > libdrm,
> > + libsdl2,
> > libevent,
> > ],
> > cpp_args : cam_cpp_args,
> > diff --git a/src/cam/sdl_sink.cpp b/src/cam/sdl_sink.cpp
> > new file mode 100644
> > index 00000000..03511974
> > --- /dev/null
> > +++ b/src/cam/sdl_sink.cpp
> > @@ -0,0 +1,198 @@
> > +/* SPDX-License-Identifier: GPL-2.0-or-later */
> > +/*
> > + * sdl_sink.cpp - SDL Sink
> > + */
> > +
> > +#include "sdl_sink.h"
> > +
> > +#include <assert.h>
> > +#include <fcntl.h>
> > +#include <iomanip>
> > +#include <iostream>
> > +#include <signal.h>
> > +#include <sstream>
> > +#include <string.h>
> > +#include <unistd.h>
> > +
> > +#include <libcamera/camera.h>
> > +#include <libcamera/formats.h>
> > +
> > +#include "event_loop.h"
> > +#include "image.h"
> > +
> > +using namespace libcamera;
> > +
> > +SDLSink::SDLSink()
> > + : sdlWindow_(nullptr), sdlRenderer_(nullptr), sdlTexture_(nullptr), sdlRect_({}), sdlInit_(false)
>
> Line wrap please. Same in quite a few locations below.
Ok.
>
> > +{
> > +}
> > +
> > +SDLSink::~SDLSink()
> > +{
> > + stop();
> > +}
> > +
> > +int SDLSink::configure(const libcamera::CameraConfiguration &cfg)
> > +{
> > + int ret = FrameSink::configure(cfg);
> > + if (ret < 0)
> > + return ret;
> > +
> > + if (cfg.size() > 1) {
> > + std::cerr << "SDL sink only supports one camera stream at present, streaming first camera stream"
> > + << std::endl;
> > + } else if (cfg.empty()) {
> > + std::cerr << "Require at least one camera stream to process" << std::endl;
> > + return -EINVAL;
> > + }
> > +
> > + const libcamera::StreamConfiguration &sCfg = cfg.at(0);
>
> You could rename 'cfg' to 'config' and 'sCfg' to 'cfg' to match
> KMSSink::configure().
Ok.
>
> > + sdlRect_.w = sCfg.size.width;
> > + sdlRect_.h = sCfg.size.height;
>
> Please add a blank line here.
Ok.
>
> > + switch (sCfg.pixelFormat) {
> > + case libcamera::formats::YUYV:
> > + pixelFormat_ = SDL_PIXELFORMAT_YUY2;
> > + pitch_ = 4 * ((sdlRect_.w + 1) / 2);
> > + break;
> > +
> > + /* From here down the fourcc values are identical between SDL, drm, libcamera */
>
> They're always identical between DRM and libcamera, that's by design :-)
> You can write
>
> /* From here down the fourcc values are identical between SDL and libcamera */
>
> or simply drop the message, as I don't think it's really relevant. In
> that case I'd move the YVYU and UYVY formats just fter YUYV as they are
> related.
Ok.
>
> > + case libcamera::formats::NV21:
> > + pixelFormat_ = SDL_PIXELFORMAT_NV21;
> > + pitch_ = sdlRect_.w;
> > + break;
> > + case libcamera::formats::NV12:
> > + pixelFormat_ = SDL_PIXELFORMAT_NV12;
> > + pitch_ = sdlRect_.w;
> > + break;
> > + case libcamera::formats::YVU420:
> > + pixelFormat_ = SDL_PIXELFORMAT_YV12;
> > + pitch_ = sdlRect_.w;
> > + break;
> > + case libcamera::formats::YVYU:
> > + pixelFormat_ = SDL_PIXELFORMAT_YVYU;
> > + pitch_ = 4 * ((sdlRect_.w + 1) / 2);
> > + break;
> > + case libcamera::formats::UYVY:
> > + pixelFormat_ = SDL_PIXELFORMAT_UYVY;
> > + pitch_ = 4 * ((sdlRect_.w + 1) / 2);
> > + break;
>
> Fhr the same of completeness, does SDL have VYUY support ? NV16 and
> NV61 would also be nice if they are supported. If not that's fine.
Ok, I'll add if they are supported.
>
> > + default:
> > + std::cerr << sCfg.pixelFormat.toString() << " not present in libcamera <-> SDL map"
> > + << std::endl;
>
> std::cerr << "Unsupported pixel format "
> << sCfg.pixelFormat.toString() << std::endl;
>
> > + return -EINVAL;
> > + };
> > +
> > + return 0;
> > +}
> > +
> > +int SDLSink::start()
> > +{
> > + int ret = SDL_Init(SDL_INIT_VIDEO);
> > + if (ret) {
> > + std::cerr << "Failed to initialize SDL: " << SDL_GetError() << std::endl;
> > + return ret;
> > + }
> > +
> > + sdlInit_ = true;
> > + sdlWindow_ = SDL_CreateWindow("", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, sdlRect_.w, sdlRect_.h, SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE);
> > + if (!sdlWindow_) {
> > + std::cerr << "Failed to create SDL window: " << SDL_GetError() << std::endl;
> > + return -EINVAL;
> > + }
> > +
> > + sdlRenderer_ = SDL_CreateRenderer(sdlWindow_, -1, 0);
> > + if (!sdlRenderer_) {
> > + std::cerr << "Failed to create SDL renderer: " << SDL_GetError() << std::endl;
> > + return -EINVAL;
> > + }
> > +
> > + ret = SDL_RenderSetLogicalSize(sdlRenderer_, sdlRect_.w, sdlRect_.h);
> > + if (ret) { /* Not critical to set, don't return in this case, set for scaling purposes */
>
> Please move the comment to the next line.
Ok.
>
> > + std::cerr << "Failed to set SDL render logical size: " << SDL_GetError() << std::endl;
> > + }
> > +
> > + sdlTexture_ = SDL_CreateTexture(sdlRenderer_, pixelFormat_, SDL_TEXTUREACCESS_STREAMING, sdlRect_.w, sdlRect_.h);
> > + if (!sdlTexture_) {
> > + std::cerr << "Failed to create SDL texture: " << SDL_GetError() << std::endl;
> > + return -EINVAL;
> > + }
> > +
> > + EventLoop::instance()->addTimerEvent(10000, std::bind(&SDLSink::processSDLEvents, this));
>
> Please use std::chrono types for the addTimerEvent duration parameter.
Are we sure we want to do this, just for the sake of using the C++
version? You end up having to cast because it's not the actual type
libevent requires, libevent requires a C timeval to be passed in.
../src/cam/event_loop.cpp:105:15: error: assigning to '__suseconds_t'
(aka 'long') from incompatible type 'const std::chrono::microseconds'
(aka 'const duration<long, ratio<1, 1000000>>')
tv.tv_usec = period;
>
> Unless I'm mistaken, the event will keep being triggered indefinitely, which means
> that SDLSink::processSDLEvents() could call SDL_PollEvent() even after
> stop() calls SDL_Quit(). That seems dangerous to me, I think we need a
> way to cancel periodic timer events.
Will look into this, this is all ran through valgrind, address
santizers, etc. didn't see anything like that pop up. But will check
again.
>
> > +
> > + return 0;
> > +}
> > +
> > +int SDLSink::stop()
> > +{
> > + if (sdlTexture_) {
> > + SDL_DestroyTexture(sdlTexture_);
> > + sdlTexture_ = nullptr;
> > + }
> > +
> > + if (sdlRenderer_) {
> > + SDL_DestroyRenderer(sdlRenderer_);
> > + sdlRenderer_ = nullptr;
> > + }
> > +
> > + if (sdlWindow_) {
> > + SDL_DestroyWindow(sdlWindow_);
> > + sdlWindow_ = nullptr;
> > + }
> > +
> > + if (sdlInit_) {
> > + SDL_Quit();
> > + sdlInit_ = false;
> > + }
> > +
> > + return FrameSink::stop();
> > +}
> > +
> > +void SDLSink::mapBuffer(FrameBuffer *buffer)
> > +{
> > + std::unique_ptr<Image> image = Image::fromFrameBuffer(buffer, Image::MapMode::ReadOnly);
> > + assert(image != nullptr);
> > +
> > + mappedBuffers_[buffer] = std::move(image);
> > +}
> > +
> > +bool SDLSink::processRequest(Request *request)
> > +{
> > + for (auto [stream, buffer] : request->buffers()) {
> > + renderBuffer(buffer);
> > + break; /* to be expanded to launch SDL window per buffer */
> > + }
> > +
> > + return true;
> > +}
> > +
> > +/*
> > + * Process SDL events, required for things like window resize and quit button
> > + */
> > +void SDLSink::processSDLEvents()
> > +{
> > + for (SDL_Event e; SDL_PollEvent(&e);) {
> > + if (e.type == SDL_QUIT) { /* click close icon then quit */
>
> Please move the comment to the next line, and s/click/Click/
>
> Actually, maybe a switch/case would be better, to prepare for adding
> support for more events ? Up to you.
I'll leave it as is, if more events prove useful and someone wants to
change to switch in future, I really don't mind.
>
> > + EventLoop::instance()->exit(0);
> > + }
> > + }
> > +}
> > +
> > +void SDLSink::renderBuffer(FrameBuffer *buffer)
> > +{
> > + Image *image = mappedBuffers_[buffer].get();
> > +
> > + for (unsigned int i = 0; i < buffer->planes().size(); ++i) {
> > + const FrameMetadata::Plane &meta = buffer->metadata().planes()[i];
> > +
> > + Span<uint8_t> data = image->data(i);
> > + if (meta.bytesused > data.size())
> > + std::cerr << "payload size " << meta.bytesused
> > + << " larger than plane size " << data.size()
> > + << std::endl;
> > +
> > + SDL_UpdateTexture(sdlTexture_, &sdlRect_, data.data(), pitch_);
>
> According to https://wiki.libsdl.org/SDL_UpdateTexture,
>
> "This is a fairly slow function, intended for use with static textures
> that do not change often.
>
> If the texture is intended to be updated often, it is preferred to
> create the texture as streaming and use the locking functions referenced
> below. While this function will work with streaming textures, for
> optimization reasons you may not get the pixels back if you lock the
> texture afterward."
>
> Have you considered this ? I don't know what difference it makes when
> updating the full texture though, maybe the added complexity isn't worth
> it.
Will look into this if it's not overly complex will try other
technique suggested in that helpful link you shared.
>
> > + SDL_RenderClear(sdlRenderer_);
> > + SDL_RenderCopy(sdlRenderer_, sdlTexture_, nullptr, nullptr);
> > + SDL_RenderPresent(sdlRenderer_);
>
> Does this really have to be repeated for each plane ? That sounds
> strange.
This code is commonly written this way, but that doesn't mean it's
most optimal like you said :)
I'll explore other techniques.
>
> > + }
> > +}
> > diff --git a/src/cam/sdl_sink.h b/src/cam/sdl_sink.h
> > new file mode 100644
> > index 00000000..c9b0ab8e
> > --- /dev/null
> > +++ b/src/cam/sdl_sink.h
> > @@ -0,0 +1,46 @@
> > +/* SPDX-License-Identifier: GPL-2.0-or-later */
> > +/*
> > + * sdl_sink.h - SDL Sink
> > + */
> > +
> > +#pragma once
> > +
> > +#include <map>
> > +#include <memory>
> > +#include <string>
> > +
> > +#include <libcamera/stream.h>
> > +
> > +#include <SDL2/SDL.h>
> > +
> > +#include "frame_sink.h"
> > +
> > +class Image;
> > +
> > +class SDLSink : public FrameSink
> > +{
> > +public:
> > + SDLSink();
> > + ~SDLSink();
> > +
> > + int configure(const libcamera::CameraConfiguration &cfg) override;
> > + int start() override;
> > + int stop() override;
> > + void mapBuffer(libcamera::FrameBuffer *buffer) override;
> > +
> > + bool processRequest(libcamera::Request *request) override;
> > +
> > +private:
> > + void renderBuffer(libcamera::FrameBuffer *buffer);
> > + void processSDLEvents();
> > +
> > + std::map<libcamera::FrameBuffer *, std::unique_ptr<Image>> mappedBuffers_;
> > +
> > + SDL_Window *sdlWindow_;
> > + SDL_Renderer *sdlRenderer_;
> > + SDL_Texture *sdlTexture_;
> > + SDL_Rect sdlRect_;
> > + SDL_PixelFormatEnum pixelFormat_;
> > + bool sdlInit_;
> > + int pitch_;
> > +};
>
> --
> Regards,
>
> Laurent Pinchart
>
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