对于切换音轨里面调用ffp_set_stream_selected()函数的解释有疑问

对于这个代码的解释有疑问： //传递两个参数tracksNum：音轨的个数，stream_index：第几个音轨 ffp_set_stream_selected(ffp, tracksNum, stream_index);

我的理解： //传递两个参数selected：切换为该音轨或者关闭该音轨，stream：第几个音轨 int ffp_set_stream_selected(FFPlayer ffp, int stream, int selected) { VideoState is = ffp->is; AVFormatContext ic = NULL; AVCodecParameters codecpar = NULL; if (!is) return -1; ic = is->ic; if (!ic) return -1;

if (stream < 0 || stream >= ic->nb_streams) {
    av_log(ffp, AV_LOG_ERROR, "invalid stream index %d >= stream number (%d)\n", stream, ic->nb_streams);
    return -1;
}

codecpar = ic->streams[stream]->codecpar;
if (selected) {

//如果选择该sream，则会先关闭当前的音轨，并打开stream指向的音轨，然后返回打开音轨函数的返回值 switch (codecpar->codec_type) { case AVMEDIA_TYPE_VIDEO: if (stream != is->video_stream && is->video_stream >= 0) stream_component_close(ffp, is->video_stream); break; case AVMEDIA_TYPE_AUDIO: if (stream != is->audio_stream && is->audio_stream >= 0) stream_component_close(ffp, is->audio_stream); break; case AVMEDIA_TYPE_SUBTITLE: if (stream != is->subtitle_stream && is->subtitle_stream >= 0) stream_component_close(ffp, is->subtitle_stream); break; default: av_log(ffp, AV_LOG_ERROR, "select invalid stream %d of video type %d\n", stream, codecpar->codec_type); return -1; } return stream_component_open(ffp, stream); } else { //如果没有选择，则会执行以下代码关闭该音轨，并返回0 switch (codecpar->codec_type) { case AVMEDIA_TYPE_VIDEO: if (stream == is->video_stream) stream_component_close(ffp, is->video_stream); break; case AVMEDIA_TYPE_AUDIO: if (stream == is->audio_stream) stream_component_close(ffp, is->audio_stream); break; case AVMEDIA_TYPE_SUBTITLE: if (stream == is->subtitle_stream) stream_component_close(ffp, is->subtitle_stream); break; default: av_log(ffp, AV_LOG_ERROR, "select invalid stream %d of audio type %d\n", stream, codecpar->codec_type); return -1; } return 0; } }

lm3515 / ijkplayer-track

对于切换音轨里面调用ffp_set_stream_selected()函数的解释有疑问 #4