< GeeXLab Reference Guide />

gh_av library

Description

gh_av is the module that manages audio/video playback. This module is based on FFmpeg and is available for all platforms: Windows, Linux, macOS, Raspberry Pi and Tinker Board.

Number of functions: 23

gh_av.decoder_close ()
gh_av.decoder_open ()
gh_av.get_codec_name ()
gh_av.get_duration ()
gh_av.get_elapsed_time ()
gh_av.get_num_frames ()
gh_av.get_streams_index ()
gh_av.pause ()
gh_av.process_frame ()
gh_av.reset_streams ()
gh_av.set_volume ()
gh_av.start_audio_video_processing ()
gh_av.stop_audio_video_processing ()
gh_av.video_get_resolution ()
gh_av.video_init_texture ()
gh_av.video_update_texture ()
gh_av.video_init_texture_rgb24 ()
gh_av.video_update_texture_rgb24 ()
gh_av.video_init_texture_yuv420 ()
gh_av.video_update_texture_yuv420 ()
gh_av.seek_frame_time ()
gh_av.set_option_1i ()
gh_av.set_option_str ()

decoder_close

Description

Cleans up and closes an audio-video object.

Syntax

gh_av.decoder_close( av_id )

Languages

Parameters

av_id [ID]: audio-video object identifier

Return Values

This function has no return value(s).

Code sample


gh_av.decoder_close(av_id)

decoder_open

Description

Opens an audio/video file.

Syntax

av_id = gh_av.decoder_open( filename, loop_mode )

Languages

Parameters

filename [STRING]: audio filename
loop_mode [BOOLEAN]: looping: 1 (true) or 0 (false)

Return Values

av_id [ID]: audio-video object identifier

Code sample


av_id = gh_av.decoder_open(filename, 1)

get_codec_name

Description

Returns the codec names of video and audio streams.

Syntax

video_codec, audio_codec = gh_av.get_codec_name( av_id )

Languages

Parameters

av_id [ID]: audio-video object identifier

Return Values

video_codec, audio_codec [STRING]: codec names

Code sample


video_codec, audio_codec = gh_av.get_codec_name(av_id)

get_duration

Description

Duration of the audio-video file.

Syntax

duration = gh_av.get_duration( av_id )

Languages

Parameters

av_id [ID]: audio-video object identifier

Return Values

duration [REAL]: duration in seconds

Code sample


duration = gh_av.get_duration(av_id)

get_elapsed_time

Description

Returns the elapsed time since the start of playing.

Syntax

elapsed_time = gh_av.get_elapsed_time( av_id )

Languages

Parameters

av_id [ID]: audio-video object identifier

Return Values

elapsed_time [REAL]: elapsed time in seconds since the start of playing

Code sample


elapsed_time = gh_av.get_elapsed_time(av_id)

get_num_frames

Description

Returns the numbers of frames of video and audio streams.

Syntax

video_frames, audio_frames = gh_av.get_num_frames( av_id )

Languages

Parameters

av_id [ID]: audio-video object identifier

Return Values

video_frames, audio_frames [INTEGER]: number of frames

Code sample


video_frames, audio_frames = gh_av.get_num_frames(av_id)

get_streams_index

Description

Returns the audio and video stream indices. Useful to know if an audio video file has an audio or a video stream.

Syntax

video_index, audio_index = gh_av.get_streams_index( av_id )

Languages

Parameters

av_id [ID]: audio-video object identifier

Return Values

video_index, audio_index [INTEGER]: video and audio streams indices: -1 if the stream is not present and >= 0 if the stream is present

Code sample


audio, video = gh_av.get_streams_index(av_id)

pause

Description

Pauses an audio-video playback.

Syntax

gh_av.pause( av_id, state )

Languages

Parameters

av_id [ID]: audio-video object identifier
state [BOOLEAN]: pause: 1 (true) or 0 (false)

Return Values

This function has no return value(s).

Code sample


gh_av.pause(av_id, 1)

process_frame

Description

Process/fetch the current audio-video frame. You can call this function in a FRAME script if you don't use start_audio_video_processing() / stop_audio_video_processing().

Syntax

gh_av.process_frame( av_id, process_video, process_audio )

Languages

Parameters

av_id [ID]: audio-video object identifier
process_video [BOOLEAN]: video stream processing: 1 (enabled) or 0 (disabled)
process_audio [BOOLEAN]: audio stream processing: 1 (enabled) or 0 (disabled)

Return Values

This function has no return value(s).

Code sample


gh_av.process_frame(av_id, 1, 1)

reset_streams

Description

Resets the audio-video streams.

Syntax

gh_av.reset_streams( av_id )

Languages

Parameters

av_id [ID]: audio-video object identifier

Return Values

This function has no return value(s).

Code sample


gh_av.reset_streams(av_id)

set_volume

Description

Sets the volume of the audio stream.

Syntax

gh_av.set_volume( av_id, volume )

Languages

Parameters

av_id [ID]: audio-video object identifier
volume [REAL]: volume from 0.0 to 1.0

Return Values

This function has no return value(s).

Code sample


gh_av.set_volume(av_id, 0.7)

start_audio_video_processing

Description

Starts the audio-video processing thread.

Syntax

gh_av.start_audio_video_processing( av_id, process_video, process_audio )

Languages

Parameters

av_id [ID]: audio-video object identifier
process_video [BOOLEAN]: video stream processing: 1 (enabled) or 0 (disabled)
process_audio [BOOLEAN]: audio stream processing: 1 (enabled) or 0 (disabled)

Return Values

This function has no return value(s).

Code sample


gh_av.start_audio_video_processing(av_id, 1, 1)

stop_audio_video_processing

Description

Stops the audio-video processing thread.

Syntax

gh_av.stop_audio_video_processing( av_id )

Languages

Parameters

av_id [ID]: audio-video object identifier

Return Values

This function has no return value(s).

Code sample


gh_av.stop_audio_video_processing(av_id)

video_get_resolution

Description

Returns the resolution in pixels of video frames.

Syntax

width, height = gh_av.video_get_resolution( av_id )

Languages

Parameters

av_id [ID]: audio-video object identifier

Return Values

width, height [INTEGER]: resolution

Code sample


duration = gh_av.video_get_resolution(av_id)

video_init_texture

Description

(DEPRECATED) Creates a texture based on video parameters. This texture can be used with all gh_texture functions.

Syntax

tex_id = gh_av.video_init_texture( av_id, pf )

Languages

Parameters

av_id [ID]: audio-video object identifier
pf [INTEGER]: pixel format

Return Values

tex_id [ID]: texture identifier

Code sample


tex_id = gh_av.video_init_texture(av_id, pf) -- DEPRECATED

video_update_texture

Description

(DEPRECATED) Updates the texture GPU memory with current video frame.

Syntax

gh_av.video_update_texture( av_id, tex_id )

Languages

Parameters

av_id [ID]: audio-video object identifier
tex_id [ID]: texture identifier

Return Values

This function has no return value(s).

Code sample


gh_av.video_update_texture(av_id, tex_id) -- DEPRECATED

video_init_texture_rgb24

Description

Creates a texture based on video parameters. This texture can be used with all gh_texture functions. The texture has the RGB24 pixel format (same than PF_U8_RGB): 3 bytes per pixel.

Syntax

gh_av.video_init_texture_rgb24( av_id )

Languages

Parameters

av_id [ID]: audio-video object identifier

Return Values

This function has no return value(s).

Code sample


tex_id = gh_av.video_init_texture_rgb24(av_id)

video_update_texture_rgb24

Description

Updates the texture GPU memory with current video frame. The texture must have the RGB24 pixel format.

Syntax

gh_av.video_update_texture_rgb24( av_id, tex_id )

Languages

Parameters

av_id [ID]: audio-video object identifier
tex_id [ID]: texture identifier

Return Values

This function has no return value(s).

Code sample


gh_av.video_update_texture_rgb24(av_id, tex_id)

video_init_texture_yuv420

Description

Creates three textures (Y, U and V) based on video parameters. These textures can be used with all gh_texture functions. Each texture has the PF_U8_R pixel format: 1 byte per pixel.

Syntax

gh_av.video_init_texture_yuv420( av_id, texY, texU, texV )

Languages

Parameters

av_id [ID]: audio-video object identifier
texY, texU, texV [ID]: the three texture identifiers

Return Values

This function has no return value(s).

Code sample


texY, texU, texV = gh_av.video_init_texture_rgb24(av_id)

video_update_texture_yuv420

Description

Updates the three YUV420 textures with current video frame. Texture must have the PF_U8_R pixel format.

Syntax

gh_av.video_update_texture_yuv420( av_id, texY, tuY, texU, tuU, texY, tuV )

Languages

Parameters

av_id [ID]: audio-video object identifier
texY [ID]: texture identifier
tuY [INTEGER]: texture unit for texY
texU [ID]: texture identifier
tuU [INTEGER]: texture unit for texU
texY [ID]: texture identifier
tuV [INTEGER]: texture unit for texV

Return Values

This function has no return value(s).

Code sample


tuY = 0			
tuU = 1			
tuV = 2			
gh_av.video_update_texture_yuv420(av_id, texY, tuY, texU, tuU, texV, tuV)

seek_frame_time

Description

Allow to seek frames in seconds.

Syntax

ret = gh_av.seek_frame_time( av_id, frame_time_sec )

Languages

Parameters

av_id [ID]: audio-video object identifier
frame_time_sec [INTEGER]: frame time in seconds

Return Values

ret [BOOLEAN]: return code: 1 (success) or 0 (error)

Code sample


"Seek the frame 20 sec before the end of the video"
frame_time_sec = video_duration_sec - 20
ret = gh_av.seek_frame_time(av_id, frame_time_sec)

set_option_1i

Description

Sets an option.

Syntax

gh_av.set_option_1i( name, x )

Languages

Parameters

name [STRING]: name of the option
x [INTEGER]: value

Return Values

This function has no return value(s).

Code sample


# Possible options:
# "num_video_threads"
# "num_audio_threads"

gh_av.set_option_1i("num_video_threads", 4)

set_option_str

Description

Sets an option.

Syntax

gh_av.set_option_str( name, x )

Languages

Parameters

name [STRING]: name of the option
x [STRING]: value

Return Values

This function has no return value(s).

Code sample


# Possible options:
# "hw_device" 
#  - possible values: "cuda"

# "video_pixel_fmt"
#  - possible values: "yuv420p" and "rgb24"

gh_av.set_option_str("hw_device", "cuda")

GeeXLab Rootard Guide | Downloads | Contact