How the virtual-channel is played?

[ntop001]

if a SoundCollection(about 10s long) is assigned to a virtual-channel (at time 0s), after a while ... until 4s, now a real-channel is free to use. How pindrop play it ? it'll be played from start or played from the audio's 4/10 position ?

[alexames]

Let me make sure I understand the question: You have a 10 second long sound loaded, and you play it. Then you stop the sound 4 seconds in. Once the sound it stopped it loses its position. Playing a new sound (even if its the same sound) will start again at the beginning. If you want to start it from the 4 second mark where you left off, you need to pause the sound instead.

[ntop001]

@alexames thx for your reply. The sound is not stoped by me, it's stoped by pindrop. I see some code as follows. these code will stop low priority channel and assign it's real-channel to a higher priority channel.

static void UpdateRealChannels(PriorityList* priority_list,
                               FreeList* real_free_list,
                               FreeList* virtual_free_list) {
  PriorityList::reverse_iterator reverse_iter = priority_list->rbegin();
  for (auto iter = priority_list->begin(); iter != priority_list->end();
       ++iter) {
    if (!iter->is_real()) {
      // First check if there are any free real channels.
      if (!real_free_list->empty()) {
        // We have a free real channel. Assign this channel id to the channel
        // that is trying to resume, clear the free channel, and push it into
        // the virtual free list.
        ChannelInternalState* free_channel = &real_free_list->front();
        iter->Devirtualize(free_channel);
        virtual_free_list->push_front(*free_channel);
        iter->Resume();
      } else {
        // If there aren't any free channels, then scan from the back of the
        // list for low priority real channels.
        reverse_iter =
            std::find_if(reverse_iter, PriorityList::reverse_iterator(iter),
                         [](const ChannelInternalState& channel) {
                           return channel.real_channel().Valid();
                         });
        if (reverse_iter == priority_list->rend()) {
          // There is no more swapping that can be done. Return.
          return;
        }
        // Found a real channel that we can give to the higher priority
        // channel.
        iter->Devirtualize(&*reverse_iter);
      }
    }
  }
}

[alexames]

Yeah, if you have too many sounds playing at once it will stop playing the lowest priority sounds. I believe in the sample file I have the number of channels set relatively low, but it could realistically be pretty large (how large depends on how much other work your app is doing - you'll have to profile to figure out the right balance).

Right now the underlying library used to mix the audio (SDL_mixer) doesn't have the ability to play a sound starting from a certain timestamp, so when a sound begins playing again it will just start from the beginning rather than from where it should.

[ntop001]

@alexames Got it.