我已经从http://ffmpeg.org/doxygen/trunk/ffplay_8c-source.html中获取了ffplay.c文件,并将其重新编辑为一个cpp文件,以嵌入到我的win32 gui应用程序中。我对其进行了以下更改。
void Ffplay::play_song(string file, HWND parent, bool* successfull)
{
int flags;
VideoState* is;
input_filename = file;
/* register all codecs, demux and protocols */
#if CONFIG_AVDEVICE
avdevice_register_all();
#endif
//avformat_network_init();
//check whether the filename is valid
if (input_filename.empty())
{
logger.log(logger.LEVEL_ERROR, "filename %s is not valid\n", file);
return;
}
if (display_disable)
{
video_disable = 1;
}
flags = SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER;
if (audio_disable)
flags &= ~SDL_INIT_AUDIO;
else
{
/* Try to work around an occasional ALSA buffer underflow issue when the
* period size is NPOT due to ALSA resampling by forcing the buffer size. */
if (!SDL_getenv("SDL_AUDIO_ALSA_SET_BUFFER_SIZE"))
SDL_setenv("SDL_AUDIO_ALSA_SET_BUFFER_SIZE", "1", 1);
}
if (display_disable)
flags &= ~SDL_INIT_VIDEO;
SDL_SetMainReady();
if (SDL_Init(flags))
{
logger.log(logger.LEVEL_ERROR, "Could not initialize SDL - %s\n", SDL_GetError());
logger.log(logger.LEVEL_ERROR, "(Did you set the DISPLAY variable?)\n");
return;
}
//Initialize optional fields of a packet with default values.
//Note, this does not touch the data and size members, which have to be initialized separately.
av_init_packet(&flush_pkt);
flush_pkt.data = (uint8_t*)&flush_pkt;
if (!display_disable)
{
int flags = SDL_WINDOW_HIDDEN;
if (alwaysontop)
#if SDL_VERSION_ATLEAST(2,0,5)
flags |= SDL_WINDOW_ALWAYS_ON_TOP;
#else
logger.log(logger.LEVEL_INFO, "SDL version doesn't support SDL_WINDOW_ALWAYS_ON_TOP. Feature will be inactive.\n");
#endif
if (borderless)
flags |= SDL_WINDOW_BORDERLESS;
else
flags |= SDL_WINDOW_RESIZABLE;
SDL_InitSubSystem(flags);
ShowWindow(parent, true);
//window = SDL_CreateWindow(program_name, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, default_width, default_height, flags);
window = SDL_CreateWindowFrom(parent);
SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "linear");
if (window) {
renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
if (!renderer)
{
logger.log(logger.LEVEL_ERROR, "Failed to initialize a hardware accelerated renderer: %s\n", SDL_GetError());
renderer = SDL_CreateRenderer(window, -1, 0);
}
if (renderer)
{
if (!SDL_GetRendererInfo(renderer, &renderer_info))
{
logger.log(logger.LEVEL_INFO, "Initialized %s renderer.\n", renderer_info.name);
}
}
}
if (!window || !renderer || !renderer_info.num_texture_formats)
{
logger.log(logger.LEVEL_ERROR, "Failed to create window or renderer: %s\n", SDL_GetError());
return;
}
}
is = stream_open(input_filename.c_str(), file_iformat);
if (!is)
{
logger.log(logger.LEVEL_ERROR, "Failed to initialize VideoState!\n");
return;
}
//the song is playing now
*successfull = true;
event_loop(is);
//the song has quit;
*successfull = false;
}
void Ffplay::static_sdl_audio_callback(void* opaque, Uint8* stream, int len)
{
static_cast<Ffplay*>(opaque)->sdl_audio_callback(opaque, stream, len);
}
关闭不会从主文件更改为关闭音频和sdl框架
void Ffplay::do_exit(VideoState* is)
{
abort = true;
if(is)
{
stream_close(is);
}
if (renderer)
SDL_DestroyRenderer(renderer);
if (window)
SDL_DestroyWindow(window);
#if CONFIG_AVFILTER
av_freep(&vfilters_list);
#endif
avformat_network_deinit();
SDL_Quit();
}
我从主gui调用以下函数
ft=std::async(launch::async, &Menu::play_song, this, songs_to_play.at(0));
menu::play_song
函数是:
void Menu::play_song(wstring song_path)
{
ready_to_play_song = false;
OutputDebugString(L"\nbefore song\n");
using std::future;
using std::async;
using std::launch;
string input{ song_path.begin(),song_path.end() };
Ffplay ffplay;
ffplay.play_song(input, h_sdl_window, &song_opened);
OutputDebugString(L"\nafter song\n");
ready_to_play_song = true;
}
问题是我只能播放一首歌。如果我再次调用menu::play_song
函数,声音会丢失,视频/艺术封面也会偶尔丢失。似乎某些资源尚未释放或类似的东西。
我已将问题定位到此功能
int Ffplay::packet_queue_get(PacketQueue* q, AVPacket* pkt, int block, int* serial)
{
MyAVPacketList* pkt1;
int ret;
int count=0;
SDL_LockMutex(q->mutex);
for (;;)
{
if (q->abort_request)
{
ret = -1;
break;
}
pkt1 = q->first_pkt;
if (pkt1) {
q->first_pkt = pkt1->next;
if (!q->first_pkt)
q->last_pkt = NULL;
q->nb_packets--;
q->size -= pkt1->pkt.size + sizeof(*pkt1);
q->duration -= pkt1->pkt.duration;
*pkt = pkt1->pkt;
if (serial)
*serial = pkt1->serial;
av_free(pkt1);
ret = 1;
break;
}
else if (!block) {
ret = 0;
break;
}
else
{
logger.log(logger.LEVEL_INFO, "packet_queue before");
SDL_CondWait(q->cond, q->mutex);
logger.log(logger.LEVEL_INFO, "packet_queue after");
}
}
SDL_UnlockMutex(q->mutex);
return ret;
}
对SDL_CondWait(q->cond, q->mutex);
的呼叫永不返回
答案 0 :(得分:1)
首先,对不起,这个问题有点含糊,因为我不能上传太多代码,因为很长很长的时间,这就是为什么我将链接发布到类似于我的原始链接的原因,唯一的区别是我已经更改了功能从C静态的到C ++的公共的。
问题出在变量SDL_AudioDeviceID audio_dev
使用
audio_dev = SDL_OpenAudioDevice(NULL, 0, &wanted_spec, &spec, SDL_AUDIO_ALLOW_FREQUENCY_CHANGE | SDL_AUDIO_ALLOW_CHANNELS_CHANGE)
未按计划分配变量,当使用SDL_CloseAudioDevice(audio_dev);
关闭音频设备时,音频设备变量为0,因此未关闭该设备,因此第二首歌丢失声音或视频可能会挂起。
这是因为使用了各种线程,这些线程调用了本地回调函数,这些函数被强制转换为SDL api预期的静态性质。
答案是将设备变量更改为静态变量static SDL_AudioDeviceID audio_dev;
,因此可以从程序中的任何位置访问变量