lavd: Add KMS screen grabber

Changelog

@@ -47,6 +47,7 @@ version <next>:
 - SUP/PGS subtitle muxer
 - convolve video filter
 - VP9 tile threading support
+- KMS screen grabber
 
 version 3.3:
 - CrystalHD decoder moved to new decode API

configure

@@ -3050,6 +3050,7 @@ gdigrab_indev_select="bmp_decoder"
 iec61883_indev_deps="libiec61883"
 jack_indev_deps="jack"
 jack_indev_deps_any="sem_timedwait dispatch_dispatch_h"
+kmsgrab_indev_deps="libdrm"
 lavfi_indev_deps="avfilter"
 libcdio_indev_deps="libcdio"
 libdc1394_indev_deps="libdc1394"

libavdevice/Makefile

@@ -32,6 +32,7 @@ OBJS-$(CONFIG_FBDEV_OUTDEV)              += fbdev_enc.o \
 OBJS-$(CONFIG_GDIGRAB_INDEV)             += gdigrab.o
 OBJS-$(CONFIG_IEC61883_INDEV)            += iec61883.o
 OBJS-$(CONFIG_JACK_INDEV)                += jack.o timefilter.o
+OBJS-$(CONFIG_KMSGRAB_INDEV)             += kmsgrab.o
 OBJS-$(CONFIG_LAVFI_INDEV)               += lavfi.o
 OBJS-$(CONFIG_OPENAL_INDEV)              += openal-dec.o
 OBJS-$(CONFIG_OPENGL_OUTDEV)             += opengl_enc.o

libavdevice/alldevices.c

@@ -53,6 +53,7 @@ static void register_all(void)
     REGISTER_INDEV   (GDIGRAB,          gdigrab);
     REGISTER_INDEV   (IEC61883,         iec61883);
     REGISTER_INDEV   (JACK,             jack);
+    REGISTER_INDEV   (KMSGRAB,          kmsgrab);
     REGISTER_INDEV   (LAVFI,            lavfi);
     REGISTER_INDEV   (OPENAL,           openal);
     REGISTER_OUTDEV  (OPENGL,           opengl);

libavdevice/kmsgrab.c

+/*
+ * KMS/DRM input device
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <drm.h>
+#include <drm_fourcc.h>
+#include <drm_mode.h>
+#include <xf86drm.h>
+#include <xf86drmMode.h>
+
+#include "libavutil/hwcontext.h"
+#include "libavutil/hwcontext_drm.h"
+#include "libavutil/internal.h"
+#include "libavutil/mathematics.h"
+#include "libavutil/opt.h"
+#include "libavutil/pixfmt.h"
+#include "libavutil/pixdesc.h"
+#include "libavutil/time.h"
+
+#include "libavformat/avformat.h"
+#include "libavformat/internal.h"
+
+typedef struct KMSGrabContext {
+    const AVClass *class;
+
+    AVBufferRef *device_ref;
+    AVHWDeviceContext *device;
+    AVDRMDeviceContext *hwctx;
+
+    AVBufferRef *frames_ref;
+    AVHWFramesContext *frames;
+
+    uint32_t plane_id;
+    uint32_t drm_format;
+    unsigned int width;
+    unsigned int height;
+
+    int64_t frame_delay;
+    int64_t frame_last;
+
+    const char *device_path;
+    enum AVPixelFormat format;
+    int64_t drm_format_modifier;
+    int64_t source_plane;
+    int64_t source_crtc;
+    AVRational framerate;
+} KMSGrabContext;
+
+static void kmsgrab_free_desc(void *opaque, uint8_t *data)
+{
+    AVDRMFrameDescriptor *desc = (AVDRMFrameDescriptor*)data;
+
+    close(desc->objects[0].fd);
+
+    av_free(desc);
+}
+
+static void kmsgrab_free_frame(void *opaque, uint8_t *data)
+{
+    AVFrame *frame = (AVFrame*)data;
+
+    av_frame_free(&frame);
+}
+
+static int kmsgrab_read_packet(AVFormatContext *avctx, AVPacket *pkt)
+{
+    KMSGrabContext *ctx = avctx->priv_data;
+    drmModePlane *plane;
+    drmModeFB *fb;
+    AVDRMFrameDescriptor *desc;
+    AVFrame *frame;
+    int64_t now;
+    int err, fd;
+
+    now = av_gettime();
+    if (ctx->frame_last) {
+        int64_t delay;
+        while (1) {
+            delay = ctx->frame_last + ctx->frame_delay - now;
+            if (delay <= 0)
+                break;
+            av_usleep(delay);
+            now = av_gettime();
+        }
+    }
+    ctx->frame_last = now;
+
+    plane = drmModeGetPlane(ctx->hwctx->fd, ctx->plane_id);
+    if (!plane) {
+        av_log(avctx, AV_LOG_ERROR, "Failed to get plane "
+               "%"PRIu32".\n", ctx->plane_id);
+        return AVERROR(EIO);
+    }
+    if (!plane->fb_id) {
+        av_log(avctx, AV_LOG_ERROR, "Plane %"PRIu32" no longer has "
+               "an associated framebuffer.\n", ctx->plane_id);
+        return AVERROR(EIO);
+    }
+
+    fb = drmModeGetFB(ctx->hwctx->fd, plane->fb_id);
+    if (!fb) {
+        av_log(avctx, AV_LOG_ERROR, "Failed to get framebuffer "
+               "%"PRIu32".\n", plane->fb_id);
+        return AVERROR(EIO);
+    }
+    if (fb->width != ctx->width || fb->height != ctx->height) {
+        av_log(avctx, AV_LOG_ERROR, "Plane %"PRIu32" framebuffer "
+               "dimensions changed: now %"PRIu32"x%"PRIu32".\n",
+               ctx->plane_id, fb->width, fb->height);
+        return AVERROR(EIO);
+    }
+    if (!fb->handle) {
+        av_log(avctx, AV_LOG_ERROR, "No handle set on framebuffer.\n");
+        return AVERROR(EIO);
+    }
+
+    err = drmPrimeHandleToFD(ctx->hwctx->fd, fb->handle, O_RDONLY, &fd);
+    if (err < 0) {
+        err = errno;
+        av_log(avctx, AV_LOG_ERROR, "Failed to get PRIME fd from "
+               "framebuffer handle: %s.\n", strerror(errno));
+        return AVERROR(err);
+    }
+
+    desc = av_mallocz(sizeof(*desc));
+    if (!desc)
+        return AVERROR(ENOMEM);
+
+    *desc = (AVDRMFrameDescriptor) {
+        .nb_objects = 1,
+        .objects[0] = {
+            .fd               = fd,
+            .size             = fb->height * fb->pitch,
+            .format_modifier  = ctx->drm_format_modifier,
+        },
+        .nb_layers = 1,
+        .layers[0] = {
+            .format           = ctx->drm_format,
+            .nb_planes        = 1,
+            .planes[0] = {
+                .object_index = 0,
+                .offset       = 0,
+                .pitch        = fb->pitch,
+            },
+        },
+    };
+
+    frame = av_frame_alloc();
+    if (!frame)
+        return AVERROR(ENOMEM);
+
+    frame->hw_frames_ctx = av_buffer_ref(ctx->frames_ref);
+    if (!frame->hw_frames_ctx)
+        return AVERROR(ENOMEM);
+
+    frame->buf[0] = av_buffer_create((uint8_t*)desc, sizeof(*desc),
+                                     &kmsgrab_free_desc, avctx, 0);
+    if (!frame->buf[0])
+        return AVERROR(ENOMEM);
+
+    frame->data[0] = (uint8_t*)desc;
+    frame->format  = AV_PIX_FMT_DRM_PRIME;
+    frame->width   = fb->width;
+    frame->height  = fb->height;
+
+    drmModeFreeFB(fb);
+    drmModeFreePlane(plane);
+
+    pkt->buf = av_buffer_create((uint8_t*)frame, sizeof(*frame),
+                                &kmsgrab_free_frame, avctx, 0);
+    if (!pkt->buf)
+        return AVERROR(ENOMEM);
+
+    pkt->data  = (uint8_t*)frame;
+    pkt->size  = sizeof(*frame);
+    pkt->pts   = now;
+    pkt->flags = AV_PKT_FLAG_TRUSTED;
+
+    return 0;
+}
+
+static const struct {
+    enum AVPixelFormat pixfmt;
+    uint32_t drm_format;
+} kmsgrab_formats[] = {
+    { AV_PIX_FMT_GRAY8,    DRM_FORMAT_R8       },
+    { AV_PIX_FMT_GRAY16LE, DRM_FORMAT_R16      },
+    { AV_PIX_FMT_RGB24,    DRM_FORMAT_RGB888   },
+    { AV_PIX_FMT_BGR24,    DRM_FORMAT_BGR888   },
+    { AV_PIX_FMT_0RGB,     DRM_FORMAT_XRGB8888 },
+    { AV_PIX_FMT_0BGR,     DRM_FORMAT_XBGR8888 },
+    { AV_PIX_FMT_RGB0,     DRM_FORMAT_RGBX8888 },
+    { AV_PIX_FMT_BGR0,     DRM_FORMAT_BGRX8888 },
+    { AV_PIX_FMT_ARGB,     DRM_FORMAT_ARGB8888 },
+    { AV_PIX_FMT_ABGR,     DRM_FORMAT_ABGR8888 },
+    { AV_PIX_FMT_RGBA,     DRM_FORMAT_RGBA8888 },
+    { AV_PIX_FMT_BGRA,     DRM_FORMAT_BGRA8888 },
+    { AV_PIX_FMT_YUYV422,  DRM_FORMAT_YUYV     },
+    { AV_PIX_FMT_YVYU422,  DRM_FORMAT_YVYU     },
+    { AV_PIX_FMT_UYVY422,  DRM_FORMAT_UYVY     },
+    { AV_PIX_FMT_NV12,     DRM_FORMAT_NV12     },
+    { AV_PIX_FMT_YUV420P,  DRM_FORMAT_YUV420   },
+    { AV_PIX_FMT_YUV422P,  DRM_FORMAT_YUV422   },
+    { AV_PIX_FMT_YUV444P,  DRM_FORMAT_YUV444   },
+};
+
+static av_cold int kmsgrab_read_header(AVFormatContext *avctx)
+{
+    KMSGrabContext *ctx = avctx->priv_data;
+    drmModePlaneRes *plane_res = NULL;
+    drmModePlane *plane = NULL;
+    drmModeFB *fb = NULL;
+    AVStream *stream;
+    int err, i;
+
+    for (i = 0; i < FF_ARRAY_ELEMS(kmsgrab_formats); i++) {
+        if (kmsgrab_formats[i].pixfmt == ctx->format) {
+            ctx->drm_format = kmsgrab_formats[i].drm_format;
+            break;
+        }
+    }
+    if (i >= FF_ARRAY_ELEMS(kmsgrab_formats)) {
+        av_log(avctx, AV_LOG_ERROR, "Unsupported format %s.\n",
+               av_get_pix_fmt_name(ctx->format));
+        return AVERROR(EINVAL);
+    }
+
+    err = av_hwdevice_ctx_create(&ctx->device_ref, AV_HWDEVICE_TYPE_DRM,
+                                 ctx->device_path, NULL, 0);
+    if (err < 0) {
+        av_log(avctx, AV_LOG_ERROR, "Failed to open DRM device.\n");
+        return err;
+    }
+    ctx->device = (AVHWDeviceContext*) ctx->device_ref->data;
+    ctx->hwctx  = (AVDRMDeviceContext*)ctx->device->hwctx;
+
+    err = drmSetClientCap(ctx->hwctx->fd,
+                          DRM_CLIENT_CAP_UNIVERSAL_PLANES, 1);
+    if (err < 0) {
+        av_log(avctx, AV_LOG_WARNING, "Failed to set universal planes "
+               "capability: primary planes will not be usable.\n");
+    }
+
+    if (ctx->source_plane > 0) {
+        plane = drmModeGetPlane(ctx->hwctx->fd, ctx->source_plane);
+        if (!plane) {
+            err = errno;
+            av_log(avctx, AV_LOG_ERROR, "Failed to get plane %"PRId64": "
+                   "%s.\n", ctx->source_plane, strerror(err));
+            err = AVERROR(err);
+            goto fail;
+        }
+
+        if (plane->fb_id == 0) {
+            av_log(avctx, AV_LOG_ERROR, "Plane %"PRId64" does not have "
+                   "an attached framebuffer.\n", ctx->source_plane);
+            err = AVERROR(EINVAL);
+            goto fail;
+        }
+    } else {
+        plane_res = drmModeGetPlaneResources(ctx->hwctx->fd);
+        if (!plane_res) {
+            av_log(avctx, AV_LOG_ERROR, "Failed to get plane "
+                   "resources: %s.\n", strerror(errno));
+            err = AVERROR(EINVAL);
+            goto fail;
+        }
+
+        for (i = 0; i < plane_res->count_planes; i++) {
+            plane = drmModeGetPlane(ctx->hwctx->fd,
+                                    plane_res->planes[i]);
+            if (!plane) {
+                err = errno;
+                av_log(avctx, AV_LOG_VERBOSE, "Failed to get "
+                       "plane %"PRIu32": %s.\n",
+                       plane_res->planes[i], strerror(err));
+                continue;
+            }
+
+            av_log(avctx, AV_LOG_DEBUG, "Plane %"PRIu32": "
+                   "CRTC %"PRIu32" FB %"PRIu32".\n",
+                   plane->plane_id, plane->crtc_id, plane->fb_id);
+
+            if ((ctx->source_crtc > 0 &&
+                 plane->crtc_id != ctx->source_crtc) ||
+                plane->fb_id == 0) {
+                // Either not connected to the target source CRTC
+                // or not active.
+                drmModeFreePlane(plane);
+                plane = NULL;
+                continue;
+            }
+
+            break;
+        }
+
+        if (i == plane_res->count_planes) {
+            if (ctx->source_crtc > 0) {
+                av_log(avctx, AV_LOG_ERROR, "No usable planes found on "
+                       "CRTC %"PRId64".\n", ctx->source_crtc);
+            } else {
+                av_log(avctx, AV_LOG_ERROR, "No usable planes found.\n");
+            }
+            err = AVERROR(EINVAL);
+            goto fail;
+        }
+
+        av_log(avctx, AV_LOG_INFO, "Using plane %"PRIu32" to "
+               "locate framebuffers.\n", plane->plane_id);
+    }
+
+    ctx->plane_id = plane->plane_id;
+
+    fb = drmModeGetFB(ctx->hwctx->fd, plane->fb_id);
+    if (!fb) {
+        err = errno;
+        av_log(avctx, AV_LOG_ERROR, "Failed to get "
+               "framebuffer %"PRIu32": %s.\n",
+               plane->fb_id, strerror(err));
+        err = AVERROR(err);
+        goto fail;
+    }
+
+    av_log(avctx, AV_LOG_INFO, "Template framebuffer is %"PRIu32": "
+           "%"PRIu32"x%"PRIu32" %"PRIu32"bpp %"PRIu32"b depth.\n",
+           fb->fb_id, fb->width, fb->height, fb->bpp, fb->depth);
+
+    ctx->width  = fb->width;
+    ctx->height = fb->height;
+
+    if (!fb->handle) {
+        av_log(avctx, AV_LOG_ERROR, "No handle set on framebuffer: "
+               "maybe you need some additional capabilities?\n");
+        err = AVERROR(EINVAL);
+        goto fail;
+    }
+
+    stream = avformat_new_stream(avctx, NULL);
+    if (!stream) {
+        err = AVERROR(ENOMEM);
+        goto fail;
+    }
+
+    stream->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
+    stream->codecpar->codec_id   = AV_CODEC_ID_WRAPPED_AVFRAME;
+    stream->codecpar->width      = fb->width;
+    stream->codecpar->height     = fb->height;
+    stream->codecpar->format     = AV_PIX_FMT_DRM_PRIME;
+
+    avpriv_set_pts_info(stream, 64, 1, 1000000);
+
+    ctx->frames_ref = av_hwframe_ctx_alloc(ctx->device_ref);
+    if (!ctx->frames_ref) {
+        err = AVERROR(ENOMEM);
+        goto fail;
+    }
+    ctx->frames = (AVHWFramesContext*)ctx->frames_ref->data;
+
+    ctx->frames->format    = AV_PIX_FMT_DRM_PRIME;
+    ctx->frames->sw_format = ctx->format,
+    ctx->frames->width     = fb->width;
+    ctx->frames->height    = fb->height;
+
+    err = av_hwframe_ctx_init(ctx->frames_ref);
+    if (err < 0) {
+        av_log(avctx, AV_LOG_ERROR, "Failed to initialise "
+               "hardware frames context: %d.\n", err);
+        goto fail;
+    }
+
+    ctx->frame_delay = av_rescale_q(1, (AVRational) { ctx->framerate.den,
+                ctx->framerate.num }, AV_TIME_BASE_Q);
+
+    err = 0;
+fail:
+    if (plane_res)
+        drmModeFreePlaneResources(plane_res);
+    if (plane)
+        drmModeFreePlane(plane);
+    if (fb)
+        drmModeFreeFB(fb);
+
+    return err;
+}
+
+static av_cold int kmsgrab_read_close(AVFormatContext *avctx)
+{
+    KMSGrabContext *ctx = avctx->priv_data;
+
+    av_buffer_unref(&ctx->frames_ref);
+    av_buffer_unref(&ctx->device_ref);
+
+    return 0;
+}
+
+#define OFFSET(x) offsetof(KMSGrabContext, x)
+#define FLAGS AV_OPT_FLAG_DECODING_PARAM
+static const AVOption options[] = {
+    { "device", "DRM device path",
+      OFFSET(device_path), AV_OPT_TYPE_STRING,
+      { .str = "/dev/dri/card0" }, 0, 0, FLAGS },
+    { "format", "Pixel format for framebuffer",
+      OFFSET(format), AV_OPT_TYPE_PIXEL_FMT,
+      { .i64 = AV_PIX_FMT_BGR0 }, 0, UINT32_MAX, FLAGS },
+    { "format_modifier", "DRM format modifier for framebuffer",
+      OFFSET(drm_format_modifier), AV_OPT_TYPE_INT64,
+      { .i64 = DRM_FORMAT_MOD_NONE }, 0, INT64_MAX, FLAGS },
+    { "crtc_id", "CRTC ID to define capture source",
+      OFFSET(source_crtc), AV_OPT_TYPE_INT64,
+      { .i64 = 0 }, 0, UINT32_MAX, FLAGS },
+    { "plane_id", "Plane ID to define capture source",
+      OFFSET(source_plane), AV_OPT_TYPE_INT64,
+      { .i64 = 0 }, 0, UINT32_MAX, FLAGS },
+    { "framerate", "Framerate to capture at",
+      OFFSET(framerate), AV_OPT_TYPE_RATIONAL,
+      { .dbl = 30.0 }, 0, 1000, FLAGS },
+    { NULL },
+};
+
+static const AVClass kmsgrab_class = {
+    .class_name = "kmsgrab indev",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+AVInputFormat ff_kmsgrab_demuxer = {
+    .name           = "kmsgrab",
+    .long_name      = NULL_IF_CONFIG_SMALL("KMS screen capture"),
+    .priv_data_size = sizeof(KMSGrabContext),
+    .read_header    = &kmsgrab_read_header,
+    .read_packet    = &kmsgrab_read_packet,
+    .read_close     = &kmsgrab_read_close,
+    .flags          = AVFMT_NOFILE,
+    .priv_class     = &kmsgrab_class,
+};

libavdevice/version.h

@@ -29,7 +29,7 @@
 
 #define LIBAVDEVICE_VERSION_MAJOR  57
 #define LIBAVDEVICE_VERSION_MINOR   8
-#define LIBAVDEVICE_VERSION_MICRO 100
+#define LIBAVDEVICE_VERSION_MICRO 101
 
 #define LIBAVDEVICE_VERSION_INT AV_VERSION_INT(LIBAVDEVICE_VERSION_MAJOR, \
                                                LIBAVDEVICE_VERSION_MINOR, \