diff options
Diffstat (limited to 'ppapi/c/dev/ppb_video_capture_dev.h')
-rw-r--r-- | ppapi/c/dev/ppb_video_capture_dev.h | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/ppapi/c/dev/ppb_video_capture_dev.h b/ppapi/c/dev/ppb_video_capture_dev.h new file mode 100644 index 0000000..21a18de --- /dev/null +++ b/ppapi/c/dev/ppb_video_capture_dev.h @@ -0,0 +1,91 @@ +/* Copyright (c) 2011 The Chromium Authors. All rights reserved. + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + */ +#ifndef PPAPI_C_DEV_PPB_VIDEO_CAPTURE_DEV_H_ +#define PPAPI_C_DEV_PPB_VIDEO_CAPTURE_DEV_H_ + +#include "ppapi/c/dev/pp_video_capture_dev.h" +#include "ppapi/c/pp_bool.h" +#include "ppapi/c/pp_instance.h" +#include "ppapi/c/pp_resource.h" +#include "ppapi/c/pp_stdint.h" + +#define PPB_VIDEO_CAPTURE_DEV_INTERFACE_0_1 "PPB_VideoCapture(Dev);0.1" +#define PPB_VIDEO_CAPTURE_DEV_INTERFACE PPB_VIDEO_CAPTURE_DEV_INTERFACE_0_1 + +/** + * Video capture interface. It goes hand-in-hand with PPP_VideoCapture_Dev. + * + * Theory of operation: + * 1- Create a VideoCapture resource using Create. + * 2- Start the capture using StartCapture. You pass in the requested info + * (resolution, frame rate), as well as suggest a number of buffers you will + * need. + * 3- Receive the OnDeviceInfo callback, in PPP_VideoCapture_Dev, which will + * give you the actual capture info (the requested one is not guaranteed), as + * well as an array of buffers allocated by the browser. + * 4- On every frame captured by the browser, OnBufferReady (in + * PPP_VideoCapture_Dev) is called with the index of the buffer from the array + * containing the new frame. The buffer is now "owned" by the plugin, and the + * browser won't reuse it until ReuseBuffer is called. + * 5- When the plugin is done with the buffer, call ReuseBuffer + * 6- Stop the capture using StopCapture. + * + * The browser may change the resolution based on the constraints of the system, + * in which case OnDeviceInfo will be called again, with new buffers. + * + * The buffers contain the pixel data for a frame. The format is planar YUV + * 4:2:0, one byte per pixel, tightly packed (width x height Y values, then + * width/2 x height/2 U values, then width/2 x height/2 V values). + */ +struct PPB_VideoCapture_Dev { + /** + * Creates a new VideoCapture. + */ + PP_Resource (*Create)(PP_Instance instance); + + /** + * Returns PP_TRUE if the given resource is a VideoCapture. + */ + PP_Bool (*IsVideoCapture)(PP_Resource video_capture); + + /** + * Starts the capture. |requested_info| is a pointer to a structure containing + * the requested resolution and frame rate. |buffer_count| is the number of + * buffers requested by the plugin. Note: it is only used as advisory, the + * browser may allocate more of fewer based on available resources. + * How many buffers depends on usage. At least 2 to make sure latency doesn't + * cause lost frames. If the plugin expects to hold on to more than one buffer + * at a time (e.g. to do multi-frame processing, like video encoding), it + * should request that many more. + * + * Returns PP_ERROR_FAILED if called when the capture was already started, or + * PP_OK on success. + */ + int32_t (*StartCapture)( + PP_Resource video_capture, + const struct PP_VideoCaptureDeviceInfo_Dev* requested_info, + uint32_t buffer_count); + + /** + * Allows the browser to reuse a buffer that was previously sent by + * PPP_VideoCapture_Dev.OnBufferReady. |buffer| is the index of the buffer in + * the array returned by PPP_VideoCapture_Dev.OnDeviceInfo. + * + * Returns PP_ERROR_BADARGUMENT if buffer is out of range (greater than the + * number of buffers returned by PPP_VideoCapture_Dev.OnDeviceInfo), or if it + * is not currently owned by the plugin. Returns PP_OK otherwise. + */ + int32_t (*ReuseBuffer)(PP_Resource video_capture, uint32_t buffer); + + /** + * Stops the capture. + * + * Returns PP_ERROR_FAILED if the capture wasn't already started, or PP_OK on + * success. + */ + int32_t (*StopCapture)(PP_Resource video_capture); +}; + +#endif /* PPAPI_C_DEV_PPB_VIDEO_CAPTURE_DEV_H_ */ |