From 6db42a2b6b22e6f1928fafcf3faa67ed78201004 Mon Sep 17 00:00:00 2001 From: Lukasz Marek Date: Thu, 3 Apr 2014 19:11:19 +0200 Subject: lavd: add device capabilities API Provides API to query device capabilities. Each device must implement callbacks to benefit from this API. Signed-off-by: Lukasz Marek --- libavdevice/avdevice.h | 128 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 128 insertions(+) (limited to 'libavdevice/avdevice.h') diff --git a/libavdevice/avdevice.h b/libavdevice/avdevice.h index 8b78067133..e194663ee3 100644 --- a/libavdevice/avdevice.h +++ b/libavdevice/avdevice.h @@ -43,6 +43,9 @@ * @} */ +#include "libavutil/log.h" +#include "libavutil/opt.h" +#include "libavutil/dict.h" #include "libavformat/avformat.h" /** @@ -227,6 +230,131 @@ int avdevice_dev_to_app_control_message(struct AVFormatContext *s, enum AVDevToAppMessageType type, void *data, size_t data_size); +/** + * Following API allows user to probe device capabilities (supported codecs, + * pixel formats, sample formats, resolutions, channel counts, etc). + * It is build on top op AVOption API. + * Queried capabilities allows to set up converters of video or audio + * parameters that fit to the device. + * + * List of capablities that can be queried: + * - Capabilities valid for both audio and video devices: + * - codec: supported audio/video codecs. + * type: AV_OPT_TYPE_INT (AVCodecID value) + * - Capabilities valid for audio devices: + * - sample_format: supported sample formats. + * type: AV_OPT_TYPE_INT (AVSampleFormat value) + * - sample_rate: supported sample rates. + * type: AV_OPT_TYPE_INT + * - channels: supported number of channels. + * type: AV_OPT_TYPE_INT + * - channel_layout: supported channel layouts. + * type: AV_OPT_TYPE_INT64 + * - Capabilities valid for video devices: + * - pixel_format: supported pixel formats. + * type: AV_OPT_TYPE_INT (AVPixelFormat value) + * - window_size: supported window sizes (describes size of the window size presented to the user). + * type: AV_OPT_TYPE_IMAGE_SIZE + * - frame_size: supported frame sizes (describes size of provided video frames). + * type: AV_OPT_TYPE_IMAGE_SIZE + * - fps: supported fps values + * type: AV_OPT_TYPE_RATIONAL + * + * Value of the capability may be set by user using av_opt_set() function + * and AVDeviceCapabilitiesQuery object. Following queries will + * limit results to the values matching already set capabilities. + * For example, setting a codec may impact number of formats or fps values + * returned during next query. Setting invalid value may limit results to zero. + * + * Example of the usage basing on opengl output device: + * + * @code + * AVFormatContext *oc = NULL; + * AVDeviceCapabilitiesQuery *caps = NULL; + * AVOptionRanges *ranges; + * int ret; + * + * if ((ret = avformat_alloc_output_context2(&oc, NULL, "opengl", NULL)) < 0) + * goto fail; + * if (avdevice_capabilities_create(&caps, oc, NULL) < 0) + * goto fail; + * + * //query codecs + * if (av_opt_query_ranges(&ranges, caps, "codec", AV_OPT_MULTI_COMPONENT_RANGE)) < 0) + * goto fail; + * //pick codec here and set it + * av_opt_set(caps, "codec", AV_CODEC_ID_RAWVIDEO, 0); + * + * //query format + * if (av_opt_query_ranges(&ranges, caps, "pixel_format", AV_OPT_MULTI_COMPONENT_RANGE)) < 0) + * goto fail; + * //pick format here and set it + * av_opt_set(caps, "pixel_format", AV_PIX_FMT_YUV420P, 0); + * + * //query and set more capabilities + * + * fail: + * //clean up code + * avdevice_capabilities_free(&query, oc); + * avformat_free_context(oc); + * @endcode + */ + +/** + * Structure describes device capabilites. + * + * It is used by devices in conjuntion with av_device_capabilities AVOption table + * to implement capabilities probing API based on AVOption API. Should not be used directly. + */ +typedef struct AVDeviceCapabilitiesQuery { + const AVClass *class; + AVFormatContext *device_context; + enum AVCodecID codec; + enum AVSampleFormat sample_format; + enum AVPixelFormat pixel_format; + int sample_rate; + int channels; + int64_t channel_layout; + int window_width; + int window_height; + int frame_width; + int frame_height; + AVRational fps; +} AVDeviceCapabilitiesQuery; + +/** + * AVOption table used by devices to implement device capabilites API. Should not be used by a user. + */ +extern const AVOption av_device_capabilities[]; + +/** + * Initialize capabilities probing API based on AVOption API. + * + * avdevice_capabilities_free() must be called when query capabilities API is + * not used anymore. + * + * @param[out] caps Device capabilities data. Pointer to a NULL pointer must be passed. + * @param s Context of the device. + * @param device_options An AVDictionary filled with device-private options. + * On return this parameter will be destroyed and replaced with a dict + * containing options that were not found. May be NULL. + * The same options must be passed later to avformat_write_header() for output + * devices or avformat_open_input() for input devices, or at any other place + * that affects device-private options. + * + * @return >= 0 on success, negative otherwise. + */ +int avdevice_capabilities_create(AVDeviceCapabilitiesQuery **caps, AVFormatContext *s, + AVDictionary **device_options); + +/** + * Free resources created by avdevice_capabilities_create() + * + * @param caps Device capabilities data to be freed. + * @param s Context of the device. + */ +void avdevice_capabilities_free(AVDeviceCapabilitiesQuery **caps, AVFormatContext *s); + /** * Structure describes basic parameters of the device. */ -- cgit v1.2.3