gstreamer 中 vp8enc 的实时视频可以使用哪些设置？
What settings can be used for live video for vp8enc in gstreamer?
我正在研究使用此元素对实时视频进行编码，在大多数情况下，输入视频相对简单时，效果很好。然而，对于我们的一些场景，编码器落后了。 （特别是我们有一个测试场景，里面有一群鸟，使编码器适合。）
查看输出，我相信这是因为该元素似乎没有针对复杂场景调整 QP。不过，我没有看到 "live" 视频的具体调整。有人有什么建议吗？
Element Properties:
name : The name of the object
flags: readable, writable
String. Default: "vp8enc0"
parent : The parent of the object
flags: readable, writable
Object of type "GstObject"
end-usage : Rate control mode
flags: readable, writable
Enum "GstVPXEncEndUsage" Default: 0, "vbr"
(0): vbr - Variable Bit Rate (VBR) mode
(1): cbr - Constant Bit Rate (CBR) mode
(2): cq - Constant Quality Mode (CQ) mode
target-bitrate : Target bitrate (in bits/sec)
flags: readable, writable
Integer. Range: 0 - 2147483647 Default: 256000
min-quantizer : Minimum Quantizer (best)
flags: readable, writable
Integer. Range: 0 - 63 Default: 4
max-quantizer : Maximum Quantizer (worst)
flags: readable, writable
Integer. Range: 0 - 63 Default: 63
dropframe-threshold : Temporal resampling threshold (buf %)
flags: readable, writable
Integer. Range: 0 - 100 Default: 0
resize-allowed : Allow spatial resampling
flags: readable, writable
Boolean. Default: false
resize-up-threshold : Upscale threshold (buf %)
flags: readable, writable
Integer. Range: 0 - 100 Default: 60
resize-down-threshold: Downscale threshold (buf %)
flags: readable, writable
Integer. Range: 0 - 100 Default: 30
undershoot : Datarate undershoot (min) target (%)
flags: readable, writable
Integer. Range: 0 - 1000 Default: 100
overshoot : Datarate overshoot (max) target (%)
flags: readable, writable
Integer. Range: 0 - 1000 Default: 100
buffer-size : Client buffer size (ms)
flags: readable, writable
Integer. Range: 0 - 2147483647 Default: 6000
buffer-initial-size : Initial client buffer size (ms)
flags: readable, writable
Integer. Range: 0 - 2147483647 Default: 4000
buffer-optimal-size : Optimal client buffer size (ms)
flags: readable, writable
Integer. Range: 0 - 2147483647 Default: 5000
twopass-vbr-bias : CBR/VBR bias (0=CBR, 100=VBR)
flags: readable, writable
Integer. Range: 0 - 100 Default: 50
twopass-vbr-minsection: GOP minimum bitrate (% target)
flags: readable, writable
Integer. Range: 0 - 2147483647 Default: 0
twopass-vbr-maxsection: GOP maximum bitrate (% target)
flags: readable, writable
Integer. Range: 0 - 2147483647 Default: 400
keyframe-mode : Keyframe placement
flags: readable, writable
Enum "GstVPXEncKfMode" Default: 1, "auto"
(1): auto - Determine optimal placement automatically
(0): disabled - Don't automatically place keyframes
keyframe-max-dist : Maximum distance between keyframes (number of frames)
flags: readable, writable
Integer. Range: 0 - 2147483647 Default: 128
temporal-scalability-number-layers: Number of coding layers to use
flags: readable, writable
Integer. Range: 1 - 5 Default: 1
temporal-scalability-target-bitrate: Target bitrates for coding layers (one per layer, decreasing)
flags: readable, writable
Array of GValues of type "gint"
temporal-scalability-rate-decimator: Rate decimation factors for each layer
flags: readable, writable
Array of GValues of type "gint"
temporal-scalability-periodicity: Length of sequence that defines layer membership periodicity
flags: readable, writable
Integer. Range: 0 - 16 Default: 0
temporal-scalability-layer-id: Sequence defining coding layer membership
flags: readable, writable
Array of GValues of type "gint"
multipass-mode : Multipass encode mode
flags: readable, writable
Enum "GstVPXEncMultipassMode" Default: 0, "one-pass"
(0): one-pass - One pass encoding (default)
(1): first-pass - First pass of multipass encoding
(2): last-pass - Last pass of multipass encoding
multipass-cache-file: Multipass cache file. If stream caps reinited, multiple files will be created: file, file.1, file.2, ... and so on.
flags: readable, writable
String. Default: "multipass.cache"
error-resilient : Error resilience flags
flags: readable, writable
Flags "GstVPXEncErFlags" Default: 0x00000000, "(none)"
(0x00000001): default - Default error resilience
(0x00000002): partitions - Allow partitions to be decoded independently
lag-in-frames : Maximum number of frames to lag
flags: readable, writable
Integer. Range: 0 - 25 Default: 0
threads : Number of threads to use
flags: readable, writable
Integer. Range: 0 - 64 Default: 0
deadline : Deadline per frame (usec, 0=disabled)
flags: readable, writable
Integer64. Range: 0 - 9223372036854775807 Default: 0
horizontal-scaling-mode: Horizontal scaling mode
flags: readable, writable
Enum "GstVPXEncScalingMode" Default: 0, "normal"
(0): normal - Normal
(1): 4:5 - 4:5
(2): 3:5 - 3:5
(3): 1:2 - 1:2
vertical-scaling-mode: Vertical scaling mode
flags: readable, writable
Enum "GstVPXEncScalingMode" Default: 0, "normal"
(0): normal - Normal
(1): 4:5 - 4:5
(2): 3:5 - 3:5
(3): 1:2 - 1:2
cpu-used : CPU used
flags: readable, writable
Integer. Range: -16 - 16 Default: 0
auto-alt-ref : Automatically generate AltRef frames
flags: readable, writable
Boolean. Default: false
noise-sensitivity : Noise sensisivity (frames to blur)
flags: readable, writable
Integer. Range: 0 - 6 Default: 0
sharpness : Filter sharpness
flags: readable, writable
Integer. Range: 0 - 7 Default: 0
static-threshold : Motion detection threshold
flags: readable, writable
Integer. Range: 0 - 2147483647 Default: 0
token-partitions : Number of token partitions
flags: readable, writable
Enum "GstVPXEncTokenPartitions" Default: 0, "1"
(0): 1 - One token partition
(1): 2 - Two token partitions
(2): 4 - Four token partitions
(3): 8 - Eight token partitions
arnr-maxframes : AltRef maximum number of frames
flags: readable, writable
Integer. Range: 0 - 15 Default: 0
arnr-strength : AltRef strength
flags: readable, writable
Integer. Range: 0 - 6 Default: 3
arnr-type : AltRef type
flags: readable, writable, deprecated
Integer. Range: 1 - 3 Default: 3
tuning : Tuning
flags: readable, writable
Enum "GstVPXEncTuning" Default: 0, "psnr"
(0): psnr - Tune for PSNR
(1): ssim - Tune for SSIM
cq-level : Constrained quality level
flags: readable, writable
Integer. Range: 0 - 63 Default: 10
max-intra-bitrate : Maximum Intra frame bitrate
flags: readable, writable
Integer. Range: 0 - 2147483647 Default: 0
timebase : Fraction of one second that is the shortest interframe time - normally left as zero which will default to the framerate
flags: readable, writable
Fraction. Range: 0/1 - 2147483647/1 Default: 0/1
这是我使用网络摄像头和 JACK 作为音频源的设置：
gst-launch-1.0 v4l2src device=/dev/video0 ! video/x-raw, format=YUY2, width=$WIDTH, height=$HEIGHT, framerate=$FRAMERATE/1 \
! queue ! videoconvert \
! queue ! vp8enc threads=4 deadline=2 \
! queue ! muxout. \
jackaudiosrc connect=1 ! audio/x-raw, format=F32LE, channels=1 \
! queue ! audiocheblimit mode=high-pass cutoff=120 poles=4 \
! queue ! audiodynamic characteristics=soft-knee mode=compressor threshold=0.16 ratio=0.15 \
! queue ! rgvolume pre-amp=6.0 headroom=1.0 \
! queue ! rglimiter \
! queue ! audioconvert \
! queue ! opusenc bitrate=96000 \
! queue ! muxout. \
webmmux streamable=true name=muxout \
! queue ! tcpserversink host=127.0.0.1 port=9000 blocksize=65536 sync-method=1 \
> /dev/null
我正在研究使用此元素对实时视频进行编码，在大多数情况下，输入视频相对简单时，效果很好。然而，对于我们的一些场景，编码器落后了。 （特别是我们有一个测试场景，里面有一群鸟，使编码器适合。）
查看输出，我相信这是因为该元素似乎没有针对复杂场景调整 QP。不过，我没有看到 "live" 视频的具体调整。有人有什么建议吗？
Element Properties:
name : The name of the object
flags: readable, writable
String. Default: "vp8enc0"
parent : The parent of the object
flags: readable, writable
Object of type "GstObject"
end-usage : Rate control mode
flags: readable, writable
Enum "GstVPXEncEndUsage" Default: 0, "vbr"
(0): vbr - Variable Bit Rate (VBR) mode
(1): cbr - Constant Bit Rate (CBR) mode
(2): cq - Constant Quality Mode (CQ) mode
target-bitrate : Target bitrate (in bits/sec)
flags: readable, writable
Integer. Range: 0 - 2147483647 Default: 256000
min-quantizer : Minimum Quantizer (best)
flags: readable, writable
Integer. Range: 0 - 63 Default: 4
max-quantizer : Maximum Quantizer (worst)
flags: readable, writable
Integer. Range: 0 - 63 Default: 63
dropframe-threshold : Temporal resampling threshold (buf %)
flags: readable, writable
Integer. Range: 0 - 100 Default: 0
resize-allowed : Allow spatial resampling
flags: readable, writable
Boolean. Default: false
resize-up-threshold : Upscale threshold (buf %)
flags: readable, writable
Integer. Range: 0 - 100 Default: 60
resize-down-threshold: Downscale threshold (buf %)
flags: readable, writable
Integer. Range: 0 - 100 Default: 30
undershoot : Datarate undershoot (min) target (%)
flags: readable, writable
Integer. Range: 0 - 1000 Default: 100
overshoot : Datarate overshoot (max) target (%)
flags: readable, writable
Integer. Range: 0 - 1000 Default: 100
buffer-size : Client buffer size (ms)
flags: readable, writable
Integer. Range: 0 - 2147483647 Default: 6000
buffer-initial-size : Initial client buffer size (ms)
flags: readable, writable
Integer. Range: 0 - 2147483647 Default: 4000
buffer-optimal-size : Optimal client buffer size (ms)
flags: readable, writable
Integer. Range: 0 - 2147483647 Default: 5000
twopass-vbr-bias : CBR/VBR bias (0=CBR, 100=VBR)
flags: readable, writable
Integer. Range: 0 - 100 Default: 50
twopass-vbr-minsection: GOP minimum bitrate (% target)
flags: readable, writable
Integer. Range: 0 - 2147483647 Default: 0
twopass-vbr-maxsection: GOP maximum bitrate (% target)
flags: readable, writable
Integer. Range: 0 - 2147483647 Default: 400
keyframe-mode : Keyframe placement
flags: readable, writable
Enum "GstVPXEncKfMode" Default: 1, "auto"
(1): auto - Determine optimal placement automatically
(0): disabled - Don't automatically place keyframes
keyframe-max-dist : Maximum distance between keyframes (number of frames)
flags: readable, writable
Integer. Range: 0 - 2147483647 Default: 128
temporal-scalability-number-layers: Number of coding layers to use
flags: readable, writable
Integer. Range: 1 - 5 Default: 1
temporal-scalability-target-bitrate: Target bitrates for coding layers (one per layer, decreasing)
flags: readable, writable
Array of GValues of type "gint"
temporal-scalability-rate-decimator: Rate decimation factors for each layer
flags: readable, writable
Array of GValues of type "gint"
temporal-scalability-periodicity: Length of sequence that defines layer membership periodicity
flags: readable, writable
Integer. Range: 0 - 16 Default: 0
temporal-scalability-layer-id: Sequence defining coding layer membership
flags: readable, writable
Array of GValues of type "gint"
multipass-mode : Multipass encode mode
flags: readable, writable
Enum "GstVPXEncMultipassMode" Default: 0, "one-pass"
(0): one-pass - One pass encoding (default)
(1): first-pass - First pass of multipass encoding
(2): last-pass - Last pass of multipass encoding
multipass-cache-file: Multipass cache file. If stream caps reinited, multiple files will be created: file, file.1, file.2, ... and so on.
flags: readable, writable
String. Default: "multipass.cache"
error-resilient : Error resilience flags
flags: readable, writable
Flags "GstVPXEncErFlags" Default: 0x00000000, "(none)"
(0x00000001): default - Default error resilience
(0x00000002): partitions - Allow partitions to be decoded independently
lag-in-frames : Maximum number of frames to lag
flags: readable, writable
Integer. Range: 0 - 25 Default: 0
threads : Number of threads to use
flags: readable, writable
Integer. Range: 0 - 64 Default: 0
deadline : Deadline per frame (usec, 0=disabled)
flags: readable, writable
Integer64. Range: 0 - 9223372036854775807 Default: 0
horizontal-scaling-mode: Horizontal scaling mode
flags: readable, writable
Enum "GstVPXEncScalingMode" Default: 0, "normal"
(0): normal - Normal
(1): 4:5 - 4:5
(2): 3:5 - 3:5
(3): 1:2 - 1:2
vertical-scaling-mode: Vertical scaling mode
flags: readable, writable
Enum "GstVPXEncScalingMode" Default: 0, "normal"
(0): normal - Normal
(1): 4:5 - 4:5
(2): 3:5 - 3:5
(3): 1:2 - 1:2
cpu-used : CPU used
flags: readable, writable
Integer. Range: -16 - 16 Default: 0
auto-alt-ref : Automatically generate AltRef frames
flags: readable, writable
Boolean. Default: false
noise-sensitivity : Noise sensisivity (frames to blur)
flags: readable, writable
Integer. Range: 0 - 6 Default: 0
sharpness : Filter sharpness
flags: readable, writable
Integer. Range: 0 - 7 Default: 0
static-threshold : Motion detection threshold
flags: readable, writable
Integer. Range: 0 - 2147483647 Default: 0
token-partitions : Number of token partitions
flags: readable, writable
Enum "GstVPXEncTokenPartitions" Default: 0, "1"
(0): 1 - One token partition
(1): 2 - Two token partitions
(2): 4 - Four token partitions
(3): 8 - Eight token partitions
arnr-maxframes : AltRef maximum number of frames
flags: readable, writable
Integer. Range: 0 - 15 Default: 0
arnr-strength : AltRef strength
flags: readable, writable
Integer. Range: 0 - 6 Default: 3
arnr-type : AltRef type
flags: readable, writable, deprecated
Integer. Range: 1 - 3 Default: 3
tuning : Tuning
flags: readable, writable
Enum "GstVPXEncTuning" Default: 0, "psnr"
(0): psnr - Tune for PSNR
(1): ssim - Tune for SSIM
cq-level : Constrained quality level
flags: readable, writable
Integer. Range: 0 - 63 Default: 10
max-intra-bitrate : Maximum Intra frame bitrate
flags: readable, writable
Integer. Range: 0 - 2147483647 Default: 0
timebase : Fraction of one second that is the shortest interframe time - normally left as zero which will default to the framerate
flags: readable, writable
Fraction. Range: 0/1 - 2147483647/1 Default: 0/1
这是我使用网络摄像头和 JACK 作为音频源的设置：
gst-launch-1.0 v4l2src device=/dev/video0 ! video/x-raw, format=YUY2, width=$WIDTH, height=$HEIGHT, framerate=$FRAMERATE/1 \
! queue ! videoconvert \
! queue ! vp8enc threads=4 deadline=2 \
! queue ! muxout. \
jackaudiosrc connect=1 ! audio/x-raw, format=F32LE, channels=1 \
! queue ! audiocheblimit mode=high-pass cutoff=120 poles=4 \
! queue ! audiodynamic characteristics=soft-knee mode=compressor threshold=0.16 ratio=0.15 \
! queue ! rgvolume pre-amp=6.0 headroom=1.0 \
! queue ! rglimiter \
! queue ! audioconvert \
! queue ! opusenc bitrate=96000 \
! queue ! muxout. \
webmmux streamable=true name=muxout \
! queue ! tcpserversink host=127.0.0.1 port=9000 blocksize=65536 sync-method=1 \
> /dev/null