extern "C"
{
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <libswresample/swresample.h>
#include <libavutil/avstring.h>
#include <libavutil/pixfmt.h>
#include <libavutil/log.h>
};
#include <stdio.h>
#include <math.h>
#include <SDL.h>
#include <SDL_thread.h>
#pragma comment(lib, "libmingwex.lib")
#pragma comment(lib, "libgcc.lib")
#pragma comment(lib, "avformat.lib")
#pragma comment(lib, "avutil.lib")
#pragma comment(lib, "avcodec.lib")
#pragma comment(lib, "swresample.lib")
#pragma comment(lib, "SDL.lib")
#pragma comment(lib, "SDLmain.lib")
#define SDL_AUDIO_BUFFER_SIZE 1024
#define MAX_AUDIOQ_SIZE (1 * 1024 * 1024)
#define FF_ALLOC_EVENT (SDL_USEREVENT)
#define FF_REFRESH_EVENT (SDL_USEREVENT + 1)
#define FF_QUIT_EVENT (SDL_USEREVENT + 2)
typedef struct PacketQueue {//Queue
AVPacketList *first_pkt, *last_pkt;
int nb_packets;
int size;
SDL_mutex *mutex;
SDL_cond *cond;
} PacketQueue;
typedef struct VideoState {//State
char filename[1024];
AVFormatContext *ic;
AVCodecContext *pCodecCtx;
AVCodec *pCodec;
int videoStream, audioStream;
AVStream *audio_st;
AVFrame *audio_frame;
PacketQueue audioq;
unsigned int audio_buf_size;
unsigned int audio_buf_index;
AVPacket audio_pkt;
uint8_t *audio_pkt_data;
int audio_pkt_size;
uint8_t *audio_buf;
uint8_t *audio_buf1;
DECLARE_ALIGNED(16,uint8_t,audio_buf2)[AVCODEC_MAX_AUDIO_FRAME_SIZE * 4];
enum AVSampleFormat audio_src_fmt;
enum AVSampleFormat audio_tgt_fmt;
int audio_src_channels;
int audio_tgt_channels;
int64_t audio_src_channel_layout;
int64_t audio_tgt_channel_layout;
int audio_src_freq;
int audio_tgt_freq;
struct SwrContext *swr_ctx;
SDL_Thread *parse_tid;//thread id
int quit;//flag
} VideoState;
VideoState *global_video_state;//global state
void packet_queue_init(PacketQueue *q) {//init queue
memset(q, 0, sizeof(PacketQueue));
q->mutex = SDL_CreateMutex();
q->cond = SDL_CreateCond();
}
int packet_queue_put(PacketQueue *q, AVPacket *pkt) {//put pkt to pktQueue
AVPacketList *pkt1;
pkt1 = (AVPacketList *)av_malloc(sizeof(AVPacketList));
if (!pkt1) {
return -1;
}
pkt1->pkt = *pkt;//put pkt to PacketList
pkt1->next = NULL;
SDL_LockMutex(q->mutex);
if (!q->last_pkt) {//last_pkt = NULL, Queue element is PacketList,we can not use packet directly
q->first_pkt = pkt1;
} else {//not first time
q->last_pkt->next = pkt1;
}
q->last_pkt = pkt1;//update
q->nb_packets++;//record nb_packet
q->size += pkt1->pkt.size;//update pkt size in queue
SDL_CondSignal(q->cond);
SDL_UnlockMutex(q->mutex);
return 0;
}
static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block) {//get data from queue
AVPacketList *pkt1;
int ret;
SDL_LockMutex(q->mutex);//lock
for(;;) {
if(global_video_state->quit) {//is or not quit firstly
ret = -1;
break;
}//quit，跳出循环
pkt1 = q->first_pkt;//queue: first in, first out
if (pkt1) {
q->first_pkt = pkt1->next;
if (!q->first_pkt) {//if queue is over
q->last_pkt = NULL;
}
q->nb_packets--;
q->size -= pkt1->pkt.size;
*pkt = pkt1->pkt;
av_free(pkt1);
ret = 1;//
break;
} else if (!block) {
ret = 0;
break;
} else {
SDL_CondWait(q->cond, q->mutex);//until data enough
}
}
SDL_UnlockMutex(q->mutex);
return ret;
}
static void packet_queue_flush(PacketQueue *q) {//flush queue
AVPacketList *pkt, *pkt1;
SDL_LockMutex(q->mutex);//lock
for (pkt = q->first_pkt; pkt != NULL; pkt = pkt1) {
pkt1 = pkt->next;
av_free_packet(&pkt->pkt);
av_freep(&pkt);
}
q->last_pkt = NULL;
q->first_pkt = NULL;
q->nb_packets = 0;
q->size = 0;
SDL_UnlockMutex(q->mutex);//unlock
}
int audio_decode_frame(VideoState *is) {//core code decoded information is saved in videostate-is
int len1, len2, decoded_data_size;
AVPacket *pkt = &is->audio_pkt;
int got_frame = 0;
int64_t dec_channel_layout;
int wanted_nb_samples, resampled_data_size;
for (;;) {//dead loop
while (is->audio_pkt_size > 0) {
if (!is->audio_frame) {
if (!(is->audio_frame = avcodec_alloc_frame())) {
return AVERROR(ENOMEM);
}
} else
avcodec_get_frame_defaults(is->audio_frame);//AVFrame should be set to default values
len1 = avcodec_decode_audio4(is->audio_st->codec, is->audio_frame, &got_frame, pkt);
if (len1 < 0) {
// error, skip the frame
is->audio_pkt_size = 0;
break;
}
is->audio_pkt_data += len1;
is->audio_pkt_size -= len1;
if (!got_frame)
continue;
/* decoded_data_size = av_samples_get_buffer_size(NULL,
is->audio_frame->channels,
is->audio_frame->nb_samples,
is->audio_frame->format, 1);*/
decoded_data_size = av_samples_get_buffer_size(NULL,
is->pCodecCtx->channels,
is->audio_frame->nb_samples,
AVSampleFormat(is->audio_frame->format), 1);//get decoded_data_size
/* dec_channel_layout = (is->audio_frame->channel_layout && is->audio_frame->channels
== av_get_channel_layout_nb_channels(is->audio_frame->channel_layout))
? is->audio_frame->channel_layout
: av_get_default_channel_layout(is->audio_frame->channels);*/
dec_channel_layout = (is->pCodecCtx->channel_layout && is->pCodecCtx->channels
== av_get_channel_layout_nb_channels(is->pCodecCtx->channel_layout))
? is->pCodecCtx->channel_layout
: av_get_default_channel_layout(is->pCodecCtx->channels);
wanted_nb_samples = is->audio_frame->nb_samples;
//fprintf(stderr, "wanted_nb_samples = %d
", wanted_nb_samples);
//解码出来的音频与原先设定的格式不一致,则重采样
if (is->audio_frame->format != is->audio_src_fmt ||
dec_channel_layout != is->audio_src_channel_layout ||
is->pCodecCtx->sample_rate != is->audio_src_freq ||
(wanted_nb_samples != is->audio_frame->nb_samples && !is->swr_ctx)) {
if (is->swr_ctx) swr_free(&is->swr_ctx);
is->swr_ctx = swr_alloc_set_opts(NULL, //get swr_ctx
is->audio_tgt_channel_layout,
is->audio_tgt_fmt,
is->audio_tgt_freq,
dec_channel_layout,
AVSampleFormat(is->audio_frame->format),
is->pCodecCtx->sample_rate,
0, NULL);
if (!is->swr_ctx || swr_init(is->swr_ctx) < 0) {//init
fprintf(stderr, "swr_init() failed
");
break;
}//get src parameters
is->audio_src_channel_layout = dec_channel_layout;
is->audio_src_channels = is->audio_st->codec->channels;
is->audio_src_freq = is->audio_st->codec->sample_rate;
is->audio_src_fmt = is->audio_st->codec->sample_fmt;
}
if (is->swr_ctx) {
// const uint8_t *in[] = { is->audio_frame->data[0] };
const uint8_t **in = (const uint8_t **)is->audio_frame->extended_data;
uint8_t *out[] = { is->audio_buf2 };
if (wanted_nb_samples != is->audio_frame->nb_samples) {//compensate samples
swr_compensate(is->swr_ctx, (wanted_nb_samples - is->audio_frame->nb_samples)
* is->audio_tgt_freq / is->pCodecCtx->sample_rate,
wanted_nb_samples * is->audio_tgt_freq / is->pCodecCtx->sample_rate);
}
len2 = swr_convert(is->swr_ctx, out,// in data is changed by swr_ctx
sizeof(is->audio_buf2)
/ is->audio_tgt_channels
/ av_get_bytes_per_sample(is->audio_tgt_fmt),//tgt_nb_samples
in, is->audio_frame->nb_samples);//convert
if (len2 < 0) {
fprintf(stderr, "swr_convert() failed
");
break;
}
if (len2 == sizeof(is->audio_buf2) / is->audio_tgt_channels / av_get_bytes_per_sample(is->audio_tgt_fmt)) {
fprintf(stderr, "warning: audio buffer is probably too small
");
swr_init(is->swr_ctx);
}
is->audio_buf = is->audio_buf2;//audio_buff
resampled_data_size = len2 * is->audio_tgt_channels * av_get_bytes_per_sample(is->audio_tgt_fmt);//resampled_data_size
} else {
resampled_data_size = decoded_data_size;//not resampled
is->audio_buf = is->audio_frame->data[0];
}
// We have data, return it and come back for more later
return resampled_data_size; //返回重采样后的长度
}//decode one frame
if (pkt->data) av_free_packet(pkt);
memset(pkt, 0, sizeof(*pkt));
if (is->quit) return -1;
if (packet_queue_get(&is->audioq, pkt, 1) < 0) return -1;//get next packet
is->audio_pkt_data = pkt->data;
is->audio_pkt_size = pkt->size;
}
}
void audio_callback(void *userdata, Uint8 *stream, int len) {
VideoState *is = (VideoState *)userdata;
int len1, audio_data_size;
printf("audio callback 1 len=%d
",len);
while (len > 0) {
if (is->audio_buf_index >= is->audio_buf_size) {
audio_data_size = audio_decode_frame(is);//decode one frame,return size
if(audio_data_size < 0) {
/* silence */
is->audio_buf_size = 1024;
memset(is->audio_buf, 0, is->audio_buf_size);
} else {
is->audio_buf_size = audio_data_size;
}
is->audio_buf_index = 0;
printf("audio callback 2 (audio_buf_size,audio_buf_index) = (%d,%d)
",is->audio_buf_size,is->audio_buf_index);
}
len1 = is->audio_buf_size - is->audio_buf_index;
if (len1 > len) {
len1 = len;
}
memcpy(stream, (uint8_t *)is->audio_buf + is->audio_buf_index, len1);
len -= len1;
stream += len1;
is->audio_buf_index += len1;
printf("audio callback 3 (len1,len,audio_buf_index) = (%d,%d,%d)
",len1,len,is->audio_buf_index);
}
}
int stream_component_open(VideoState *is, int stream_index) {//open stream
AVFormatContext *ic = is->ic;
AVCodecContext *codecCtx;
AVCodec *codec;
SDL_AudioSpec wanted_spec, spec;
int64_t wanted_channel_layout = 0;
int wanted_nb_channels;
const int next_nb_channels[] = {0, 0, 1 ,6, 2, 6, 4, 6};
if (stream_index < 0 || stream_index >= ic->nb_streams) {
return -1;
}
codecCtx = ic->streams[stream_index]->codec;
is->pCodecCtx=codecCtx;//Add
wanted_nb_channels = codecCtx->channels;//wanted parameters
if(!wanted_channel_layout || wanted_nb_channels != av_get_channel_layout_nb_channels(wanted_channel_layout)) {
wanted_channel_layout = av_get_default_channel_layout(wanted_nb_channels);
wanted_channel_layout &= ~AV_CH_LAYOUT_STEREO_DOWNMIX;
}
wanted_spec.channels = av_get_channel_layout_nb_channels(wanted_channel_layout);
wanted_spec.freq = codecCtx->sample_rate;
if (wanted_spec.freq <= 0 || wanted_spec.channels <= 0) {
fprintf(stderr, "Invalid sample rate or channel count!
");
return -1;
}
wanted_spec.format = AUDIO_S16SYS;
wanted_spec.silence = 0;
wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE;
wanted_spec.callback = audio_callback;//callback
wanted_spec.userdata = is;
while(SDL_OpenAudio(&wanted_spec, &spec) < 0) {//OpenAudio
fprintf(stderr, "SDL_OpenAudio (%d channels): %s
", wanted_spec.channels, SDL_GetError());
wanted_spec.channels = next_nb_channels[FFMIN(7, wanted_spec.channels)];
if(!wanted_spec.channels) {
fprintf(stderr, "No more channel combinations to tyu, audio open failed
");
return -1;
}
wanted_channel_layout = av_get_default_channel_layout(wanted_spec.channels);
}
if (spec.format != AUDIO_S16SYS) {
fprintf(stderr, "SDL advised audio format %d is not supported!
", spec.format);
return -1;
}
if (spec.channels != wanted_spec.channels) {
wanted_channel_layout = av_get_default_channel_layout(spec.channels);
if (!wanted_channel_layout) {
fprintf(stderr, "SDL advised channel count %d is not supported!
", spec.channels);
return -1;
}
}
fprintf(stderr, "%d: wanted_spec.format = %d
", __LINE__, wanted_spec.format);
fprintf(stderr, "%d: wanted_spec.samples = %d
", __LINE__, wanted_spec.samples);
fprintf(stderr, "%d: wanted_spec.channels = %d
", __LINE__, wanted_spec.channels);
fprintf(stderr, "%d: wanted_spec.freq = %d
", __LINE__, wanted_spec.freq);
fprintf(stderr, "%d: spec.format = %d
", __LINE__, spec.format);
fprintf(stderr, "%d: spec.samples = %d
", __LINE__, spec.samples);
fprintf(stderr, "%d: spec.channels = %d
", __LINE__, spec.channels);
fprintf(stderr, "%d: spec.freq = %d
", __LINE__, spec.freq);
is->audio_src_fmt = is->audio_tgt_fmt = AV_SAMPLE_FMT_S16;//src parameters
is->audio_src_freq = is->audio_tgt_freq = spec.freq;
is->audio_src_channel_layout = is->audio_tgt_channel_layout = wanted_channel_layout;
is->audio_src_channels = is->audio_tgt_channels = spec.channels;
codec = avcodec_find_decoder(codecCtx->codec_id);//find decoder
is->pCodec=codec;//Add
if (!codec || (avcodec_open2(codecCtx, codec, NULL) < 0)) {//Unsupported codec
fprintf(stderr, "Unsupported codec!
");
return -1;
}
ic->streams[stream_index]->discard = AVDISCARD_DEFAULT;
switch(codecCtx->codec_type) {
case AVMEDIA_TYPE_AUDIO:
is->audioStream = stream_index;
is->audio_st = ic->streams[stream_index];
is->audio_buf_size = 0;
is->audio_buf_index = 0;
memset(&is->audio_pkt, 0, sizeof(is->audio_pkt));
packet_queue_init(&is->audioq);
SDL_PauseAudio(0);
break;
default:
break;
}
}
/*
static void stream_component_close(VideoState *is, int stream_index) {
AVFormatContext *oc = is->;
AVCodecContext *avctx;
if(stream_index < 0 || stream_index >= ic->nb_streams) return;
avctx = ic->streams[stream_index]->codec;
}
*/
static int decode_thread(void *arg) {
//初始化参数，函数内部处理得到的相关参数赋给 is
VideoState *is = (VideoState *)arg;
AVFormatContext *ic = NULL;
AVPacket pkt1, *packet = &pkt1;
int ret, i, audio_index = -1;
is->audioStream=-1;
global_video_state = is;//全局状态
if (avformat_open_input(&ic, is->filename, NULL, NULL) != 0) {
return -1;
}
is->ic = ic;
if (avformat_find_stream_info(ic, NULL) < 0) {//打开流信息
return -1;
}
av_dump_format(ic, 0, is->filename, 0);
for (i=0; i<ic->nb_streams; i++) {
if (ic->streams[i]->codec->codec_type==AVMEDIA_TYPE_AUDIO && audio_index < 0) {//打开第一条音频流
audio_index=i;
break;
}
}
if (audio_index >= 0) {
stream_component_open(is, audio_index);//打开音频流
}
if (is->audioStream < 0) {
fprintf(stderr, "%s: could not open codecs
", is->filename);
goto fail;
}
// main decode loop
for(;;) {
if(is->quit) break;
if (is->audioq.size > MAX_AUDIOQ_SIZE) {
SDL_Delay(10);//so fast
continue;
}
ret = av_read_frame(is->ic, packet);//read data to one packet
if (ret < 0) {
if(ret == AVERROR_EOF || url_feof(is->ic->pb)) {//error or end
break;
}
if(is->ic->pb && is->ic->pb->error) {
break;
}
continue;
}
if (packet->stream_index == is->audioStream) {//packet data to audioq
packet_queue_put(&is->audioq, packet);
} else {
av_free_packet(packet);
}
}
while (!is->quit) {// delay
SDL_Delay(100);
}
fail: {//if fail
SDL_Event event;
event.type = FF_QUIT_EVENT;
event.user.data1 = is;
SDL_PushEvent(&event);
}
return 0;
}
int main(int argc, char *argv[])
{
SDL_Event event;
VideoState *is;
is = (VideoState *)av_mallocz(sizeof(VideoState));
//if (argc < 2) {
// fprintf(stderr, "Usage: test <file>
");
// exit(1);
//}
argv[1]="test.mp4";
av_register_all();//注册编解码库
if (SDL_Init(SDL_INIT_AUDIO)) { //初始化音频SDL
fprintf(stderr, "Could not initialize SDL - %s
", SDL_GetError());
exit(1);
}
av_strlcpy(is->filename,argv[1], sizeof(is->filename));
is->parse_tid = SDL_CreateThread(decode_thread, is);
if (!is->parse_tid) {
av_free(is);
return -1;
}
for(;;) {
SDL_WaitEvent(&event);
switch(event.type) {
case FF_QUIT_EVENT:
case SDL_QUIT://退出
is->quit = 1;
SDL_Quit();
exit(0);
break;
default:
break;
}
}
return 0;
}