1、开始解码的线程
static int decoder_start(Decoder *d, int (*fn)(void *), void *arg)
{
packet_queue_start(d->queue);
d->decoder_tid = SDL_CreateThread(fn, "decoder", arg);
if (!d->decoder_tid) {
av_log(NULL, AV_LOG_ERROR, "SDL_CreateThread(): %s\n", SDL_GetError());
return AVERROR(ENOMEM);
}
return 0;
}2、音频解码线程
static int audio_thread(void *arg)
{
VideoState *is = arg;
AVFrame *frame = av_frame_alloc();
Frame *af;
#if CONFIG_AVFILTER
int last_serial = -1;
int64_t dec_channel_layout;
int reconfigure;
#endif
int got_frame = 0;
AVRational tb;
int ret = 0;
if (!frame)
return AVERROR(ENOMEM);
do {
if ((got_frame = decoder_decode_frame(&is->auddec, frame, NULL)) < 0)
goto the_end;
if (got_frame) {
tb = (AVRational){1, frame->sample_rate};
#if CONFIG_AVFILTER
dec_channel_layout = get_valid_channel_layout(frame->channel_layout, frame->channels);
reconfigure =
cmp_audio_fmts(is->audio_filter_src.fmt, is->audio_filter_src.channels,
frame->format, frame->channels) ||
is->audio_filter_src.channel_layout != dec_channel_layout ||
is->audio_filter_src.freq != frame->sample_rate ||
is->auddec.pkt_serial != last_serial;
if (reconfigure) {
char buf1[1024], buf2[1024];
av_get_channel_layout_string(buf1, sizeof(buf1), -1, is->audio_filter_src.channel_layout);
av_get_channel_layout_string(buf2, sizeof(buf2), -1, dec_channel_layout);
av_log(NULL, AV_LOG_DEBUG,
"Audio frame changed from rate:%d ch:%d fmt:%s layout:%s serial:%d to rate:%d ch:%d fmt:%s layout:%s serial:%d\n",
is->audio_filter_src.freq, is->audio_filter_src.channels, av_get_sample_fmt_name(is->audio_filter_src.fmt), buf1, last_serial,
frame->sample_rate, frame->channels, av_get_sample_fmt_name(frame->format), buf2, is->auddec.pkt_serial);
is->audio_filter_src.fmt = frame->format;
is->audio_filter_src.channels = frame->channels;
is->audio_filter_src.channel_layout = dec_channel_layout;
is->audio_filter_src.freq = frame->sample_rate;
last_serial = is->auddec.pkt_serial;
if ((ret = configure_audio_filters(is, afilters, 1)) < 0)
goto the_end;
}
if ((ret = av_buffersrc_add_frame(is->in_audio_filter, frame)) < 0)
goto the_end;
while ((ret = av_buffersink_get_frame_flags(is->out_audio_filter, frame, 0)) >= 0) {
tb = av_buffersink_get_time_base(is->out_audio_filter);
#endif
if (!(af = frame_queue_peek_writable(&is->sampq)))
goto the_end;
af->pts = (frame->pts == AV_NOPTS_VALUE) ? NAN : frame->pts * av_q2d(tb);
af->pos = frame->pkt_pos;
af->serial = is->auddec.pkt_serial;
af->duration = av_q2d((AVRational){frame->nb_samples, frame->sample_rate});
av_frame_move_ref(af->frame, frame);
frame_queue_push(&is->sampq);
#if CONFIG_AVFILTER
if (is->audioq.serial != is->auddec.pkt_serial)
break;
}
if (ret == AVERROR_EOF)
is->auddec.finished = is->auddec.pkt_serial;
#endif
}
} while (ret >= 0 || ret == AVERROR(EAGAIN) || ret == AVERROR_EOF);
the_end:
#if CONFIG_AVFILTER
avfilter_graph_free(&is->agraph);
#endif
av_frame_free(&frame);
return ret;
}3、视频解码线程
static int video_thread(void *arg)
{
VideoState *is = arg;
AVFrame *frame = av_frame_alloc();
double pts;
double duration;
int ret;
AVRational tb = is->video_st->time_base;
AVRational frame_rate = av_guess_frame_rate(is->ic, is->video_st, NULL);
#if CONFIG_AVFILTER
AVFilterGraph *graph = avfilter_graph_alloc();
AVFilterContext *filt_out = NULL, *filt_in = NULL;
int last_w = 0;
int last_h = 0;
enum AVPixelFormat last_format = -2;
int last_serial = -1;
int last_vfilter_idx = 0;
if (!graph) {
av_frame_free(&frame);
return AVERROR(ENOMEM);
}
#endif
if (!frame) {
#if CONFIG_AVFILTER
avfilter_graph_free(&graph);
#endif
return AVERROR(ENOMEM);
}
for (;;) {
ret = get_video_frame(is, frame);
if (ret < 0)
goto the_end;
if (!ret)
continue;
#if CONFIG_AVFILTER
if ( last_w != frame->width
|| last_h != frame->height
|| last_format != frame->format
|| last_serial != is->viddec.pkt_serial
|| last_vfilter_idx != is->vfilter_idx) {
av_log(NULL, AV_LOG_DEBUG,
"Video frame changed from size:%dx%d format:%s serial:%d to size:%dx%d format:%s serial:%d\n",
last_w, last_h,
(const char *)av_x_if_null(av_get_pix_fmt_name(last_format), "none"), last_serial,
frame->width, frame->height,
(const char *)av_x_if_null(av_get_pix_fmt_name(frame->format), "none"), is->viddec.pkt_serial);
avfilter_graph_free(&graph);
graph = avfilter_graph_alloc();
if ((ret = configure_video_filters(graph, is, vfilters_list ? vfilters_list[is->vfilter_idx] : NULL, frame)) < 0) {
SDL_Event event;
event.type = FF_QUIT_EVENT;
event.user.data1 = is;
SDL_PushEvent(&event);
goto the_end;
}
filt_in = is->in_video_filter;
filt_out = is->out_video_filter;
last_w = frame->width;
last_h = frame->height;
last_format = frame->format;
last_serial = is->viddec.pkt_serial;
last_vfilter_idx = is->vfilter_idx;
frame_rate = av_buffersink_get_frame_rate(filt_out);
}
ret = av_buffersrc_add_frame(filt_in, frame);
if (ret < 0)
goto the_end;
while (ret >= 0) {
is->frame_last_returned_time = av_gettime_relative() / 1000000.0;
ret = av_buffersink_get_frame_flags(filt_out, frame, 0);
if (ret < 0) {
if (ret == AVERROR_EOF)
is->viddec.finished = is->viddec.pkt_serial;
ret = 0;
break;
}
is->frame_last_filter_delay = av_gettime_relative() / 1000000.0 - is->frame_last_returned_time;
if (fabs(is->frame_last_filter_delay) > AV_NOSYNC_THRESHOLD / 10.0)
is->frame_last_filter_delay = 0;
tb = av_buffersink_get_time_base(filt_out);
#endif
duration = (frame_rate.num && frame_rate.den ? av_q2d((AVRational){frame_rate.den, frame_rate.num}) : 0);
pts = (frame->pts == AV_NOPTS_VALUE) ? NAN : frame->pts * av_q2d(tb);
ret = queue_picture(is, frame, pts, duration, frame->pkt_pos, is->viddec.pkt_serial);
av_frame_unref(frame);
#if CONFIG_AVFILTER
}
#endif
if (ret < 0)
goto the_end;
}
the_end:
#if CONFIG_AVFILTER
avfilter_graph_free(&graph);
#endif
av_frame_free(&frame);
return 0;
}4、子标题解码线程
static int subtitle_thread(void *arg)
{
VideoState *is = arg;
Frame *sp;
int got_subtitle;
double pts;
for (;;) {
if (!(sp = frame_queue_peek_writable(&is->subpq)))
return 0;
if ((got_subtitle = decoder_decode_frame(&is->subdec, NULL, &sp->sub)) < 0)
break;
pts = 0;
if (got_subtitle && sp->sub.format == 0) {
if (sp->sub.pts != AV_NOPTS_VALUE)
pts = sp->sub.pts / (double)AV_TIME_BASE;
sp->pts = pts;
sp->serial = is->subdec.pkt_serial;
sp->width = is->subdec.avctx->width;
sp->height = is->subdec.avctx->height;
sp->uploaded = 0;
/* now we can update the picture count */
frame_queue_push(&is->subpq);
} else if (got_subtitle) {
avsubtitle_free(&sp->sub);
}
}
return 0;
}