Membrane.H264.FFmpeg.Encoder (Membrane H264 FFmpeg plugin v0.15.0) View Source

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

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 choosen, 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 setting max_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

`:input`

Availability	`:always`
Caps	`Membrane.Caps.Video.Raw`, restrictions:<br />  `format: one_of([:I420, :I422])`,<br />  `aligned: true`
Demand unit	`:buffers`
Direction	`:input`
Mode	`:pull`
Name	`:input`

`:output`

Availability	`:always`
Caps	`Membrane.Caps.Video.H264`, restrictions:<br />  `stream_format: :byte_stream`,<br />  `alignment: :au`
Direction	`:output`
Mode	`:pull`
Name	`:output`

Link to this section Summary

Types

presets()

t()

Struct containing options for Membrane.H264.FFmpeg.Encoder

Functions

membrane_pads()

Returns pads descriptions for Membrane.H264.FFmpeg.Encoder

options()

Returns description of options available for this module

Link to this section Types

presets()

Specs

presets() ::
  :placebo
  | :veryslow
  | :slower
  | :slow
  | :medium
  | :fast
  | :faster
  | :veryfast
  | :superfast
  | :ultrafast

t()

Specs

t() :: %Membrane.H264.FFmpeg.Encoder{
  crf: any(),
  max_b_frames: any(),
  preset: presets(),
  profile: Membrane.Caps.Video.H264.profile_t() | nil,
  use_shm?: boolean()
}

Struct containing options for Membrane.H264.FFmpeg.Encoder

Link to this section Functions

membrane_pads()

Specs

membrane_pads() :: [{Membrane.Pad.name_t(), Membrane.Pad.description_t()}]

Returns pads descriptions for Membrane.H264.FFmpeg.Encoder

options()

Specs

options() :: keyword()

Returns description of options available for this module