[FFmpeg-devel] [PATCH] doc/encoders: add VP9 temporal scalability encoding option
Wonkap Jang
wonkap at google.com
Tue Dec 17 00:21:41 EET 2019
Documentation change for adding support for encoding
with temporal scalability in VP9.
---
doc/encoders.texi | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)
diff --git a/doc/encoders.texi b/doc/encoders.texi
index 4ee518a124..7efc446a6c 100644
--- a/doc/encoders.texi
+++ b/doc/encoders.texi
@@ -1885,16 +1885,14 @@ Enable error resiliency features.
Increase sharpness at the expense of lower PSNR.
The valid range is [0, 7].
- at item VP8-specific options
- at table @option
@item ts-parameters
Sets the temporal scalability configuration using a :-separated list of
key=value pairs. For example, to specify temporal scalability parameters
with @code{ffmpeg}:
@example
ffmpeg -i INPUT -c:v libvpx -ts-parameters ts_number_layers=3:\
-ts_target_bitrate=250000,500000,1000000:ts_rate_decimator=4,2,1:\
-ts_periodicity=4:ts_layer_id=0,2,1,2 OUTPUT
+ts_target_bitrate=250,500,1000:ts_rate_decimator=4,2,1:\
+ts_periodicity=4:ts_layer_id=0,2,1,2:ts_layering_mode=3 OUTPUT
@end example
Below is a brief explanation of each of the parameters, please
refer to @code{struct vpx_codec_enc_cfg} in @code{vpx/vpx_encoder.h} for more
@@ -1903,13 +1901,28 @@ details.
@item ts_number_layers
Number of temporal coding layers.
@item ts_target_bitrate
-Target bitrate for each temporal layer.
+Target bitrate for each temporal layer in kbps.
+(bitrate should be inclusive of the lower temporal layer).
@item ts_rate_decimator
Frame rate decimation factor for each temporal layer.
@item ts_periodicity
Length of the sequence defining frame temporal layer membership.
@item ts_layer_id
Template defining the membership of frames to temporal layers.
+ at item ts_layering_mode
+(optional) Selecting the temporal structure from a set of pre-defined temporal layering modes.
+Currently supports the following options.
+ at table @option
+ at item 0
+No temporal layering flags are provided internally,
+relies on flags being passed in using metadata in AVFrame.
+ at item 2
+Two temporal layers. 0-1...
+ at item 3
+Three temporal layers. 0-2-1-2...; with single reference frame.
+ at item 4
+Same as option "3", except there is a dependency between
+the two temporal layer 2 frames within the temporal period.
@end table
@end table
--
2.24.1.735.g03f4e72817-goog
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