Unable to select and play an item from a playlist

This forum is about all development around libVLC.
hansdampf
New Cone
New Cone
Posts: 2
Joined: 30 May 2020 23:29
VLC version: 3.0.10
Operating System: Windows

Unable to select and play an item from a playlist

Postby hansdampf » 31 May 2020 20:27

I work with Python 3.8.2 in Windows and Python 3.7.3 on my Raspberry Pi 4.
I am happy and successful with my internet radio based on vlc and now struggling with the music cdrom part. :cry:

I can select and play any audio track with the MediaPlayer. I can also create and play the whole audio cd with a playlist.
But I am still unable to select and play an item of the created playlist.

root = Tk() and root.mainloop() are only embedded, of course, I deleted all of the developed GUI elements to simplify the presentation.

I created three simple examples to make my problem clear.
Example 1 works fine for every selected track.
Example 2 works also fine for the playlist as a whole.

Example 3 shows my problem. Even after reading the documented vlc Binding for Python I still stuck.
I simply do not understand what parameter(s) I have to use.
Neither for

Code: Select all

'play_item_at_index'
nor for

Code: Select all

'play_item'
It sounds so simple for me, but I am unable to put in the right pieces of information to get a result.

Maybe an expert here can give me a hint of the meaning of the error message.
And hopefully, someone can give me useful advice on how to handle these commands.
Or tell me a better way to manage the playlist.

Code: Select all

import vlc import platform from tkinter import * root = Tk() # define parameters depending on OS if platform.system() == 'Windows': instance = vlc.Instance('--quiet') cd_lw = 'cdda:///E:/' else: instance = vlc.Instance('--quiet', '--aout=alsa') cd_lw = 'cdda:///dev/sr0/' mrl = ':cdda-track=' # Example 1 # player settings player = instance.media_player_new() player.set_mrl(cd_lw, mrl + str(4)) # this works fine, track nr. 4 is played # player.play() # Example 2 # creating a playlist with all the audio tracks on the audio cd # listplayer settings listplayer = instance.media_list_player_new() # media list setings playlist = instance.media_list_new() tracks = instance.media_new(cd_lw) # adds all tracks of the audio cd to the playlist playlist.add_media(tracks) listplayer.set_media_list(playlist) # this works also fine, all tracks are played and then the program ended # listplayer.play() # Example 3 # here starts my problem. I did not find a way to tell # vlc playing a selected song from the previous created playlist ''' info from http://www.olivieraubert.net/vlc/python-ctypes/doc/ 3242 - def play_item_at_index(self, i_index): 3243 Play media list item at position index. 3244 @param i_index: index in media list to play. 3245 @return: 0 upon success -1 if the item wasn't found. 3246 3247 return libvlc_media_list_player_play_item_at_index(self, i_index) ... 3257 - def play_item(self, p_md): 3258 Play the given media item. 3259 @param p_md: the media instance. 3260 @return: 0 upon success, -1 if the media is not part of the media list. 3261 3262 return libvlc_media_list_player_play_item(self, p_md) ''' # this works with index=0 and plays the playlist # but with no other index # listplayer.play_item_at_index(0) # this does not work at all listplayer.play_item(4) ''' And give this error message Traceback (most recent call last): File "D:/Python-Programme/gui-beispiel/CD-Project/question2.py", line 62, in <module> listplayer.play_item(4) File "D:\Python-Programme\gui-beispiel\venv\lib\site-packages\vlc.py", line 3262, in play_item return libvlc_media_list_player_play_item(self, p_md) File "D:\Python-Programme\gui-beispiel\venv\lib\site-packages\vlc.py", line 8362, in libvlc_media_list_player_play_item return f(p_mlp, p_md) ctypes.ArgumentError: argument 2: <class 'AttributeError'>: 'int' object has no attribute '_as_parameter_' ''' root.mainloop()

Return to “Development around libVLC”

Who is online

Users browsing this forum: No registered users and 15 guests