Video face detection: findface-video-manager and findface-video-worker

Note

The findface-video-worker is delivered in a CPU-accelerated (findface-video-worker-cpu) and a GPU-accelerated (findface-video-worker-gpu) packages.

In this section:

Functions of findface-video-manager

The findface-video-manager service is the part of the video face detection module that is used for managing the video face detection functionality.

The findface-video-manager service interfaces with findface-video-worker as follows:

  • It supplies findface-video-worker with settings and the list of to-be-processed video streams. To do so, it issues a so-called job, a video processing task that contains configuration settings and stream data.
  • In a distributed system, it distributes video streams (jobs) across vacant findface-video-worker instances.

Note

Configuration settings passed via jobs have priority over the findface-video-manager configuration file.

The findface-video-mananger service functioning requires ETCD, third-party software that implements a distributed key-value store for findface-video-manager. In the FindFace core, ETCD is used as a coordination service, providing the video face detector with fault tolerance.

Functionality:

  • allows for configuring video face detection parameters,
  • allows for managing the list of to-be-processed video streams,
  • implements video face detection management.

Functions of findface-video-worker

The findface-video-worker service (on CPU/GPU) is the part of the video face detection module, that recognizes faces in the video. It can work with both live streams and files, and supports most video formats and codecs that can be decoded by FFmpeg.

The findface-video-worker service interfaces with the findface-video-manager and findface-facerouter services as follows:

  • By request, findface-video-worker gets a job with settings and the list of to-be-processed video streams from findface-video-manager.
  • The findface-video-worker posts extracted normalized face images, along with the full frames and meta data (such as bbox, camera ID and detection time) to the findface-facerouter service for further processing.

Note

In FindFace Security, the findface-facerouter functions are performs by findface-security.

Functionality:

  • detects faces in video,
  • extracts normalized face images,
  • searches for the best face snapshot,
  • snapshot deduplication (only one snapshot per face detection event).

When processing video, findface-video-worker consequently uses the following algorithms:

  • Motion detection. Used to reduce resource consumption. Only when the motion detector recognizes the motion of certain intensity that the face tracker can be triggered.
  • Face tracking. The face tracker tracks, detects and captures faces in the video. It can simultaneously be working with several faces. It also searches for the best face snapshot, using an embedded neural network. After the best face snapshot is found, it is posted to findface-facerouter.

The best face snapshot can be found in one of the following modes:

  • Real-time
  • Offline

Real-Time Mode

In the real-time mode, findface-video-worker posts a face immediately after it appears in the camera field of view.

  • If rt-perm=True, the face tracker searches for the best face snapshot within each time period equal to rt-delay and posts it to findface-facerouter.
  • If rt-perm=False, the face tracker searches for the best face snapshot dynamically:
    1. First, the face tracker estimates whether the quality of a face snapshot exceeds a pre-defined threshold value. If so, the snapshot is posted to findface-facerouter.
    2. The threshold value increases after each post. Each time the face tracker gets a higher quality snapshot of the same face, it is posted.
    3. When the face disappears from the camera field of view, the threshold value resets to default.

By default, the real-time mode is disabled (realtime=false in the /etc/findface-video-manager.conf file).

Offline Mode

The offline mode is less storage intensive than the real-time one as in this mode findface-video-worker posts only one snapshot per track, but of the highest quality. In this mode, the face tracker buffers a video stream with a face in it until the face disappears from the camera field of view. Then the face tracker picks up the best face snapshot from the buffered video and posts it to findface-facerouter.

By default, the offline mode is enabled (overall=true in the /etc/findface-video-manager.conf file).

Configure Video Face Detection

The video face detector configuration is done through the following configuration files:

  1. The findface-video-manager configuration file /etc/findface-video-manager.conf:

    listen: 127.0.0.1:18810
etcd:
  endpoints: 127.0.0.1:2379
  dial_timeout: 3s
kafka:
   enabled: false
   endpoints: 127.0.0.1:9092
master:
  lease_ttl: 10
  self_url: 127.0.0.1:18811
  self_url_http: 127.0.0.1:18811
rpc:
  listen: 127.0.0.1:18811
  heart_beat_timeout: 4s
router_url: http://127.0.0.1:18820/v0/frame
exp_backoff:
  enabled: false
  min_delay: 1s
  max_delay: 1m0s
  factor: 2
  flush_interval: 2m0s
ntls:
  enabled: false
  url: http://127.0.0.1:3185/
  update_interval: 1m0s
prometheus:
  jobs_processed_duration_buckets:
  - 1
  - 30
  - 60
  - 500
  - 1800
  - 3600
  - 21600
  - .inf
job_scheduler_script: ''
stream_settings:
  ffmpeg_params: []
  md_threshold: 0.002
  md_scale: 0.3
  fd_frame_height: -1
  uc_max_time_diff: 30
  uc_max_dup: 3
  uc_max_avg_shift: 10
  det_period: 8
  realtime: false
  npersons: 4
  disable_drops: false
  tracker_threads: 4
  parse_sei: false
  image_arg: photo
  additional_headers: []
  additional_body: []
  api_timeout: 15000
  api_ssl_verify: true
  post_uniq: true
  min_score: -2
  min_d_score: -1000
  realtime_dly: 500
  realtime_post_perm: false
  rot: ''
  roi: ''
  draw_track: false
  send_track: 0
  min_face_size: 0
  max_face_size: 0
  overall: true
  only_norm: false
  max_candidates: 0
  jpeg_quality: 95
  ffmpeg_format: ''
stream_settings_gpu:
  play_speed: -1
  filter_min_quality: -2
  filter_min_face_size: 1
  filter_max_face_size: 8192
  normalized_only: false
  jpeg_quality: 95
  overall_only: true
  use_stream_timestamp: false
  ffmpeg_params: []
  router_timeout_ms: 15000
  router_verify_ssl: true
  router_headers: []
  router_body: []
  start_stream_timestamp: 0
  imotion_threshold: 0
  rot: ''
  roi: ''
  realtime_post_interval: 1
  realtime_post_every_interval: false
  ffmpeg_format: ''
  disable_drops: false

When configuring findface-video-manager, refer to the following parameters:

Option Description
router_url IP address and port of the findface-facerouter host to receive detected faces from findface-video-worker. In FindFace Security, findface-facerouter functions are performed by findface-security. Default value: http://127.0.0.1:18820/v0/frame.
etcd -> endpoints IP address and port of the etcd service. Default value: 127.0.0.1:2379.
ntls -> enabled If true, findface-video-manager will send a job to findface-video-worker only if the total number of processed cameras does not exceed the allowed number of cameras from the license. Default value: false.
ntls -> url IP address and port of the findface-ntls host. Default value: http://127.0.0.1:3185/.

You can also configure the following parameters:

Note

In the stream_settings(-gpu) section of the file, you will find settings common to all video streams. Settings of a particular stream, passed in a job, have priority over those in the configuration file (see Jobs).

CPU-option GPU-option Description
additional_body router_body Additional body fields in a request body when posting a face: [“key = value”]. Default value: body fields not specified.
additional_headers router_headers Additional header fields in a request when posting a face: [“key = value”]. Default value: headers not specified.
api_ssl_verify router_verify_ssl Enables a https certificate verification when findface-video-worker and findface-facerouter (or findface-security in the standard FindFace Security configuration) interact over https. Default value: true. If false, a self-signed certificate can be accepted.
api_timeout router_timeout_ms Timeout for a findface-facerouter (or findface-security in the standard FindFace Security configuration) response to a findface-video-worker API request, in milliseconds. If the timeout has expired, the system will log an error. Default value: 15000.
disable_drops disable_drops Enables posting all appropriate faces without drops. By default, if findface-video-worker does not have enough resources to process all frames with faces, it drops some of them. If this option is active, findface-video-worker puts odd frames on the waiting list to process them later. Default value: false.
draw_track N/a Enables drawing a face motion track in a bbox. Default value: false.
fd_frame_height N/a Video frame height for the face tracker, in pixels. Scale down in the case of high resolution cameras, or close up faces, or if the CPU load is too high, to reduce the system resources consumption. Make sure that the scaled face size exceeds the min-face-size value. Default value: -1 (negative values corresponds to the original size). Optimal value to reduce load: 640-720.
ffmpeg_format ffmpeg_format Pass FFMPEG format (mxg, flv, etc.) if it cannot be detected automatically.
ffmpeg_params ffmpeg_params List of a video stream ffmpeg options with their values as a key=value array: [“rtsp_transpotr=tcp”, .., “ss=00:20:00”]. Check out the FFmpeg web site for the full list of options. Default value: options not specified.
image_arg N/a Name of the argument containing a bbox with a face, in an API request. Default value: photo.
jpeg_quality jpeg_quality Quality of an original frame JPEG compression, in percents. Default value: 95%.
max_face_size filter_max_face_size Maximum size of a face in pixels. Oversized faces are not posted. Default value: 0 (filter disabled).
md_scale N/a Video frame scaling coefficient for the motion detector, relative to the original size from 0 to 1. Scale down in the case of high resolution cameras, or close up faces, or if the CPU load is too high, to reduce the system resources consumption. Make sure that the scaled face size exceeds the min-face-size value. Default value: 1 (original size).
md_threshold imotion_threshold Minimum motion intensity to be detected by the motion detector. The threshold value is to be fitted empirically. Empirical units: zero and positive rational numbers. Milestones: 0 = detector disabled, 0.002 = default value, 0.05 = minimum intensity is too high to detect motion.
min_score filter_min_quality Minimum threshold value for a face image quality. A face is posted if it has better quality. The threshold value is to be fitted empirically. Empirical units: negative rational numbers to zero. Milestones: 0 = high quality faces, -1 = good quality, -2 = satisfactory quality, -5 = face recognition maybe inefficient. Default value: -2.
min_face_size filter_min_face_size Minimum size of a face in pixels. Undersized faces are not posted. Default value: 0 (filter disabled).
min_d_score N/a Maximum deviation of a face from its frontal position. A face is posted if its deviation is less than this value. The deviation is to be fitted empirically. Empirical units: negative rational numbers to zero. Milestones: -3.5 = large face angles, face recognition may be inefficient, -2.5 = satisfactory deviation, -0.05 = close to the frontal position, 0 = frontal face. Default value: -1000.
npersons N/a Maximum number of faces simultaneously tracked by the face tracker. This parameter severely affects performance. Default value: 4.
only_norm normalized_only Enable posting only normalized face images without full frames. Default value: false.
overall overall_only Enables the offline mode for the best face search. Default value: true.
N/a play_speed If less than zero, the speed is not limited. In other cases, the stream is read with the given play_speed. Not applicable for live streams.
post_uniq N/a Enables face deduplication, i.e. posting only a certain number of faces belonging to one person, during a certain period of time. In this case, if findface-video-worker posts a face to findface-facerouter and then tracks another one within the time period uc_max_time_diff, and the distance between the two faces doesn’t exceed uc_max_avg_shift, findface-video-worker estimates their similarity. If the faces are similar and the total number of similar faces during the uc_max_time_diff period does not exceed the number uc_max_dup, findface-video-worker posts the other face. Otherwise, the other face is not posted. Default value: true.
realtime N/a Enables the real-time mode for the best face search. Default value: false.
realtime_dly realtime_post_interval Only for the real-time mode. If realtime_post_perm=True, defines the time period in milliseconds within which the face tracker picks up the best snapshot and posts it to findface-facerouter. If realtime_post_perm=False, defines the minimum time period between 2 posts of the same face with increased quality. Default value: 500.
realtime_post_perm realtime_post_every_interval Only for the realtime mode. Post best snapshots obtained within each realtime_dly time period. If false, search for the best snapshot dynamically and send snapshots in order of increasing quality. Default value: false.
roi roi Enable posting faces detected only inside a region of interest WxH+X+Y. Default value: region not specified.
rot rot Enables detecting and tracking faces only inside a clipping rectangle WxH+X+Y. You can use this option to reduce findface-video-worker load. Default value: rectangle not specified.
send_track N/a Enables posting a face motion track as array of the bbox center coordinates. As the send_track value, specify the number of dots in the motion track. Default value: 0 (array not posted).
N/a start_stream_timestamp Add the specified number of seconds to timestamps from a stream.
tracker_threads N/a Number of tracking threads for the face tracker. This value should be less or equal to the npersons value. We recommend you to set them equal. If the number of tracking threads is less than the maximum number of tracked faces, resource consumption is reduced but so is the tracking speed. Default value: 1.
uc_max_time_diff N/a Only if post_uniq: true (face deduplication enabled). Maximum time period in seconds during which a number of similar faces are considered as belonging to one person. Default value: 30.
uc_max_dup N/a Only if post_uniq: true (face deduplication enabled). Maximum number of faces during the uc_max_time_diff period that is posted for a person. Default value: 3.
uc_max_avg_shift N/a Only if post_uniq: true (face deduplication enabled). Distance in pixels within which a number of similar faces are considered as belonging to one person. Default value: 10.
N/a use_stream_timestamp If true, retrieve and post timestamps from a video stream. If false, post the actual date and time.

  1. If you opt for the CPU-accelerated package findface-video-worker-cpu, use the /etc/findface-video-worker-cpu.ini configuration file:

    ## read streams from file, do not use VideoManager
input =

## exit on first finished job, only when --input specified
exit_on_first_finished = false

## batch size
batch_size = 4

## http server port for metrics, 0=do not start server
metrics_port = 0

## resize scale, 1=do not resize
resize_scale = 1.000000

## maximum number of streams
capacity = 10

## command to obtain videomanager's grpc ip:port
mgr_cmd =

## videomanager grpc ip:port
mgr_static = 127.0.0.1:18811

## ntls server ip:port
ntls_addr = 127.0.0.1:3133

## debug: save faces to dir
save_dir =

## minimum face size
min_face_size = 60

## preinit detector for specified resolutions: "640x480;1920x1080"
resolutions =

## worker labels: "k=v;group=enter"
labels =

## use timestamps from SEI packet
use_time_from_sei = false

#------------------------------
[streamer]
#------------------------------
## streamer server port, 0=disabled
port = 18999

## streamer url - how to access this worker on streamer_port
url = ws://127.0.0.1:18999/stream/

#------------------------------
[liveness]
#------------------------------
## path to liveness fnk
fnk =

## liveness threshold
threshold = 0.945000

## liveness internal algo param
interval = 1.000000

## liveness internal algo param
stdev_cnt = 1

#------------------------------
[send]
#------------------------------
## posting faces threads
threads = 8

## posting faces maximum queue size
queue_limit = 256

#------------------------------
[tracker]
#------------------------------
## max face miss duration, sec
miss_interval = 1.000000

## overlap threshold
overlap_threshold = 0.250000

#------------------------------
[models]
#------------------------------
## path to detector fnk
detector = /usr/share/findface-data/models/facedet/mtcnn.cpu.fnk

## path to quality fnk
quality = /usr/share/findface-data/models/faceattr/quality.v0.cpu.fnk

## path to norm for quality fnk
norm_quality = /usr/share/findface-data/models/facenorm/ant.v2.cpu.fnk

## path to norm200 fnk, for face send
norm_200 = /usr/share/findface-data/models/facenorm/ant.v2.cpu.fnk

## path to norm_crop2x fnk, for face send
norm_crop2x = /usr/share/findface-data/models/facenorm/crop2x.v2_maxsize400.cpu.fnk

    If you opt for the GPU-accelerated package findface-video-worker-gpu, use the /etc/findface-video-worker-gpu.ini configuration file.

    ## cuda device number
device_number = 0

## old gpu detector models directory
models_dir = /usr/share/findface-gpudetector/models

## read streams from file, do not use VideoManager
input =

## exit on first finished job, only when --input specified
exit_on_first_finished = false

## batch size
batch_size = 8

## http server port for metrics, 0=do not start server
metrics_port =

## resize scale, 1=do not resize
resize_scale = 1.000000

## maximum number of streams
capacity = 30

## command to obtain videomanager's grpc ip:port
mgr_cmd =

## videomanager grpc ip:port
mgr_static = 127.0.0.1:18811

## ntls server ip:port
ntls_addr = 127.0.0.1:3133

## debug: save faces to dir
save_dir =

## minimum face size
min_face_size = 60

## preinit detector for specified resolutions: "640x480;1920x1080"
resolutions =

## worker labels: "k=v;group=enter"
labels =

## use timestamps from SEI packet
use_time_from_sei = false

#------------------------------
[streamer]
#------------------------------
## streamer server port, 0=disabled
port = 18999

## streamer url - how to access this worker on streamer_port
url = ws://172.17.46.17:18999/stream/

#------------------------------
[liveness]
#------------------------------
## path to liveness fnk
fnk =

## liveness threshold
threshold = 0.945000

## liveness internal algo param
interval = 1.000000

## liveness internal algo param
stdev_cnt = 1

#------------------------------
[send]
#------------------------------
## posting faces threads
threads = 8

## posting faces maximum queue size
queue_limit = 256

#------------------------------
[tracker]
#------------------------------
## max face miss duration, sec
miss_interval = 1.000000

## overlap threshold
overlap_threshold = 0.250000

#------------------------------
[models]
#------------------------------
## path to detector fnk
detector =

## path to quality fnk
quality =

## path to norm for quality fnk
norm_quality =

## path to norm200 fnk, for face send
norm_200 = /usr/share/findface-data/models/facenorm/ant.v2.gpu.fnk

## path to norm_crop2x fnk, for face send
norm_crop2x = /usr/share/findface-data/models/facenorm/crop2x.v2_maxsize400.gpu.fnk

## path to cache directory
cache_dir =

#------------------------------
[video_decoder]
#------------------------------
## decode video on cpu
cpu = false

    When configuring findface-video-worker (on CPU/GPU), refer to the following parameters:

    CPU GPU Description
    ntls-addr IP address and port of the findface-ntls host.
    mgr-static IP address of the findface-video-manager host to provide findface-video-worker with settings and the list of to-be-processed streams.
    capacity Maximum number of video streams to be processed by findface-video-worker.
    mgr-exec (Optional, instead of the mgr-static parameter) A script to describe dynamic IP address of the findface-video-manager host.
    labels Labels used to allocate a video face detector instance to a certain group of cameras. See Allocate findface-video-worker to Camera Group.
    N/a fnk Path to the face liveness detector.
    input Process streams from file, ignoring stream data from findface-video-manager.
    exit_on_first_finished (Only if input is specified) Exit on the first finished job.
    resize_scale Rescale video frames with the given coefficient.
    save_dir (For debug) Save detected faces to the given directory.
    min_face_size Minimum face size to be detected.
    resolutions Preinitialize the findface-video-worker for specific resolutions to speed up its performance.
    N/a device_number GPU device number to use.
    N/a models_dir Old directory with GPU detector models. Otherwise, use the [models] section.
    N/a cpu If necessary, decode video on CPU.

Jobs

The findface-video-manager service provides findface-video-worker with a so-called job, a video processing task that contains configuration settings and stream data.

The content of a typical job is shown in the example below.

curl http://127.0.0.1:18810/job/1 | jq
 % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                              Dload  Upload   Total   Spent    Left  Speed
 100  1771  100  1771    0     0   447k      0 --:--:-- --:--:-- --:--:--  576k
{
  "id": "1",
  "enabled": true,
  "stream_url": "rtmp://restreamer.int.ntl/cams/openspace",
  "labels": {},
  "router_url": "http://172.17.46.13/video-detector/frame",
  "single_pass": false,
  "stream_settings": {
    "ffmpeg_params": [],
    "md_threshold": 0.002,
    "md_scale": 0.3,
    "fd_frame_height": -1,
    "uc_max_time_diff": 30,
    "uc_max_dup": 3,
    "uc_max_avg_shift": 10,
    "det_period": 8,
    "realtime": false,
    "npersons": 4,
    "disable_drops": false,
    "tracker_threads": 4,
    "parse_sei": false,
    "image_arg": "photo",
    "additional_headers": [
      "Authorization=Token b612396adc3a6dd71b82b5fe333a0a30"
    ],
    "additional_body": [],
    "api_timeout": 15000,
    "api_ssl_verify": true,
    "post_uniq": true,
    "min_score": -2,
    "min_d_score": -1000,
    "realtime_dly": 500,
    "realtime_post_perm": false,
    "rot": "",
    "roi": "",
    "draw_track": false,
    "send_track": 0,
    "min_face_size": 0,
    "max_face_size": 0,
    "overall": true,
    "only_norm": false,
    "max_candidates": 0,
    "jpeg_quality": 95,
    "ffmpeg_format": ""
  },
  "stream_settings_gpu": {
    "play_speed": -1,
    "filter_min_quality": -2,
    "filter_min_face_size": 1,
    "filter_max_face_size": 8192,
    "normalized_only": false,
    "jpeg_quality": 95,
    "overall_only": false,
    "use_stream_timestamp": false,
    "ffmpeg_params": [],
    "router_timeout_ms": 15000,
    "router_verify_ssl": true,
    "router_headers": [
      "Authorization=Token b612396adc3a6dd71b82b5fe333a0a30"
    ],
    "router_body": [],
    "start_stream_timestamp": 0,
    "imotion_threshold": 0,
    "rot": "",
    "roi": "",
    "realtime_post_interval": 1,
    "realtime_post_every_interval": false,
    "ffmpeg_format": "",
    "disable_drops": true
  },
  "status": "INPROGRESS",
  "status_msg": "",
  "statistic": {
    "processed_duration": 14879,
    "faces_posted": 777,
    "faces_failed": 3,
    "faces_not_posted": 1206,
    "processing_fps": 18.816668,
    "frames_dropped": 0,
    "frames_processed": 0,
    "frames_imotion_skipped": 0,
    "decoding_soft_errors": 0,
    "job_starts": 56
  },
  "restream_url": "",
  "worker_id": "ffsec40_213ab8c0ed5d954e",
  "version": "bl068taaa7tcafrfsmq0"
}

Each job has the following parameters:

  • id: job id.
  • enabled: active status.
  • stream_url: URL/address of video stream/file to process.
  • labels: tag(s) that will be used by the findface-facerouter component (findface-security in the standard FindFace Security configuration) to find processing directives for faces detected in this stream.
  • single_pass: if true, disable restarting video processing upon error (by default, false).
  • router_url: IP address and port of the findface-facerouter component (findface-security in the standard FindFace Security configuration) to receive detected faces from the findface-video-worker component for processing.
  • stream_settings, stream_settings_gpu: video stream settings that duplicate those in the findface-video-manager configuration file (while having priority over them).
  • status: job status.
  • status_msg: additional job status info.
  • statistic: job progress statistics (progress duration, number of posted and not posted faces, processing fps, the number of processed and dropped frames, job start time, etc.).
  • worker_id: id of the findface-video-worker instance executing the job.