View Source Membrane.H264.FFmpeg.Encoder (Membrane H264 FFmpeg plugin v0.21.1)
Membrane element that encodes raw video frames to H264 format.
The element expects each frame to be received in a separate buffer, so the parser
(Membrane.Element.RawVideo.Parser
) may be required in a pipeline before
the encoder (e.g. when input is read from Membrane.File.Source
).
Additionally, the encoder has to receive proper caps with picture format and dimensions before any encoding takes place.
Please check t/0
for available options.
element-options
Element options
Passed via struct Membrane.H264.FFmpeg.Encoder.t/0
crf
any
Default value:
23
Constant rate factor that affects the quality of output stream. Value of 0 is lossless compression while 51 (for 8-bit samples) or 63 (10-bit) offers the worst quality. The range is exponential, so increasing the CRF value +6 results in roughly half the bitrate / file size, while -6 leads to roughly twice the bitrate.preset
presets()
Default value:
:medium
Collection of predefined options providing certain encoding. The slower the preset chosen, the higher compression for the same quality can be achieved.profile
H264.profile_t() | nil
Default value:
nil
Sets a limit on the features that the encoder will use to the ones supported in a provided H264 profile. Said features will have to be supported by the decoder in order to decode the resulting video. It may override other, more specific options affecting compression (e.g settingmax_b_frames
to 2 while profile is set to:baseline
will have no effect and no B-frames will be present).use_shm?
boolean
Default value:
false
max_b_frames
any
Default value:
nil
Maximum number of B-frames between non-B-frames. Set to 0 to encode video without b-frames
pads
Pads
input
:input
Availability | :always |
Caps | Membrane.RawVideo , restrictions:pixel_format: one_of([:I420, :I422]) ,aligned: true |
Demand mode | :auto |
Demand unit | :buffers |
Direction | :input |
Mode | :pull |
Name | :input |
output
:output
Availability | :always |
Caps | Membrane.H264 , restrictions:stream_format: :byte_stream ,alignment: :au |
Demand mode | :auto |
Demand unit | :buffers |
Direction | :output |
Mode | :pull |
Name | :output |
Link to this section Summary
Functions
Returns pads descriptions for Membrane.H264.FFmpeg.Encoder
Returns description of options available for this module
Link to this section Types
@type presets() ::
:placebo
| :veryslow
| :slower
| :slow
| :medium
| :fast
| :faster
| :veryfast
| :superfast
| :ultrafast
@type t() :: %Membrane.H264.FFmpeg.Encoder{ crf: any(), max_b_frames: any(), preset: presets(), profile: Membrane.H264.profile_t() | nil, use_shm?: boolean() }
Struct containing options for Membrane.H264.FFmpeg.Encoder
Link to this section Functions
@spec membrane_pads() :: [{Membrane.Pad.name_t(), Membrane.Pad.description_t()}]
Returns pads descriptions for Membrane.H264.FFmpeg.Encoder
@spec options() :: keyword()
Returns description of options available for this module