ffmpeg学习---4Spawning Threads

1. 4spawing.c

// tutorial01.c
// Code based on a tutorial by Martin Bohme ([e-mail])
// Tested on Gentoo, CVS version 5/01/07 compiled with GCC 4.1.1

// A small sample program that shows how to use libavformat and libavcodec to
// read video from a file.
//
// Use
//
// gcc -o tutorial01 tutorial01.c -lavformat -lavcodec -lz
//
// to build (assuming libavformat and libavcodec are correctly installed
// your system).
//
// Run using
//
// tutorial01 myvideofile.mpg
//
// to write the first five frames from "myvideofile.mpg" to disk in PPM
// format.
#include <stdio.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <libavutil/avstring.h>

#include <SDL.h>
#include <SDL_thread.h>
#define  SDL_AUDIO_BUFFER_SIZE  1024
#define MAX_AUDIOQ_SIZE (5 * 16 * 1024)
#define MAX_VIDEOQ_SIZE (5 * 256 * 1024)

#define FF_ALLOC_EVENT (SDL_USEREVENT)
#define FF_REFRESH_EVENT (SDL_USEREVENT + 1)
#define FF_QUIT_EVENT (SDL_USEREVENT + 2)

#define VIDEO_PICTURE_QUEUE_SIZE 1
typedef struct PacketQueue
{
    AVPacketList * first_pkt, *last_pkt;
    int nb_packets;
    int size;
    SDL_mutex *mutex;
    SDL_cond * cond;
}PacketQueue;
typedef struct VideoPicture {
    SDL_Overlay *bmp;
    int width, height; /* source height & width */
    int allocated;
} VideoPicture;

typedef struct VideoState {

    AVFormatContext *pFormatCtx;
    int videoStream, audioStream;
    AVStream *audio_st;
    PacketQueue     audioq;
    uint8_t         audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2];
    unsigned int audio_buf_size;
    unsigned int audio_buf_index;
    AVPacket        audio_pkt;
    uint8_t *audio_pkt_data;
    int audio_pkt_size;
    AVStream *video_st;
    PacketQueue     videoq;

    VideoPicture    pictq[VIDEO_PICTURE_QUEUE_SIZE];
    int pictq_size, pictq_rindex, pictq_windex;
    SDL_mutex *pictq_mutex;
    SDL_cond *pictq_cond;

    SDL_Thread *parse_tid;
    SDL_Thread *video_tid;

    char            filename[1024];
    int quit;
} VideoState;

SDL_Surface *screen;

/* Since we only have one decoding thread, the Big Struct
   can be global in case we need it. */
VideoState *global_video_state;
void packet_queue_init(PacketQueue *q)
{
    memset(q, 0, sizeof(PacketQueue));
    q->mutex = SDL_CreateMutex();
    q->cond = SDL_CreateCond();
}

int packet_queue_put(PacketQueue *q, AVPacket *pkt)
{

    AVPacketList *pkt1;
    if(av_dup_packet(pkt) < 0)
        return -1;
    pkt1 = av_malloc(sizeof(AVPacketList));
    if (!pkt1)
        return -1;
    pkt1->pkt = *pkt;
    pkt1->next = NULL;

    SDL_LockMutex(q->mutex);

    if (!q->last_pkt)
        q->first_pkt = pkt1;
    else
        q->last_pkt->next = pkt1;
    q->last_pkt = pkt1;
    q->nb_packets++;
    q->size += pkt1->pkt.size;
    SDL_CondSignal(q->cond);

    SDL_UnlockMutex(q->mutex);
    return 0;
}


static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block)
{
    AVPacketList *pkt1;
    int ret;

    SDL_LockMutex(q->mutex);

    for(;;)
    {

        if(global_video_state->quit)
        {
            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;
            *pkt = pkt1->pkt;
            av_free(pkt1);
            ret = 1;
            break;
        } else if (!block) {
            ret = 0;
            break;
        } else {
            SDL_CondWait(q->cond, q->mutex);
        }
    }
    SDL_UnlockMutex(q->mutex);
    return ret;
}


//int audio_decode_frame(AVCodecContext *aCodecCtx, uint8_t *audio_buf, int buf_size) {
//int audio_decode_frame(AVCodecContext *aCodecCtx, AVPacket *pkt, AVPacket *pkt_temp, AVFrame *frame, uint8_t *audio_buf)
int audio_decode_frame(VideoState *is, AVPacket *pkt, AVPacket *pkt_temp, AVFrame *frame, uint8_t *audio_buf)
    //int audio_decode_frame(VideoState *is, uint8_t *audio_buf, int buf_size) {
{
    int len1, data_size, got_frame;
    int new_packet;
    for(;;)
    {
        while(pkt_temp->size>0 || (!pkt_temp->data && new_packet))
        {
            if(!frame)
            {
                if (!(frame = avcodec_alloc_frame()))
                    return AVERROR(ENOMEM);
            }
            else
            {
                avcodec_get_frame_defaults(frame);
            }
            new_packet = 0;
            //data_size = buf_size;
            //int avcodec_decode_audio4(AVCodecContext *avctx, AVFrame *frame, int *got_frame_ptr, const AVPacket *avpkt);
            //len1 = avcodec_decode_audio2(aCodecCtx, (int16_t *)audio_buf, &data_size, audio_pkt_data, audio_pkt_size);
            len1 = avcodec_decode_audio4(is->audio_st->codec, frame, &got_frame, pkt_temp);
            if(len1 < 0)
            {
                /* if error, skip frame */
                pkt_temp->size = 0;
                break;
            }
            pkt_temp->data += len1;
            pkt_temp->size -= len1;

            if(got_frame <= 0) /* No data yet, get more frames */
                continue;
            data_size = av_samples_get_buffer_size(NULL, is->audio_st->codec->channels, frame->nb_samples, is->audio_st->codec->sample_fmt, 1);
            memcpy(audio_buf, frame->data[0], frame->linesize[0]);
            /* We have data, return it and come back for more later */
            return data_size;
        }
        if(pkt->data)
            av_free_packet(pkt);
        memset(pkt_temp, 0, sizeof(*pkt_temp));
        if(is->quit)
            return -1;

        if((new_packet = packet_queue_get(&is->audioq, pkt, 1)) < 0)
            return -1;
        *pkt_temp = *pkt;
    }
}

void audio_callback(void *userdata, Uint8 *stream, int len)
{
    VideoState *is = (VideoState *)userdata;
    //AVCodecContext *aCodecCtx = (AVCodecContext *)userdata;
    int len1, audio_size;

    AVPacket *pkt = av_mallocz(sizeof(AVPacket));
    AVPacket *pkt_temp = av_mallocz(sizeof(AVPacket));
    AVFrame *frame = NULL;

    while(len > 0)
    {
        if(is->audio_buf_index >= is->audio_buf_size)
        {
            /* We have already sent all our data; get more */
            //audio_size = audio_decode_frame(aCodecCtx, audio_buf, sizeof(audio_buf));
            audio_size = audio_decode_frame(is, pkt, pkt_temp, frame, is->audio_buf);
            if(audio_size < 0)
            {
                /* If error, output silence */
                is->audio_buf_size = 1024;
                memset(is->audio_buf, 0, is->audio_buf_size);
            } else {
                is->audio_buf_size = audio_size;
            }
            is->audio_buf_index = 0;
        }
        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;
    }
}

static Uint32 sdl_refresh_timer_cb(Uint32 interval, void *opaque)
{
    SDL_Event event;
    event.type = FF_REFRESH_EVENT;
    event.user.data1 = opaque;
    SDL_PushEvent(&event);
    return 0; /* 0 means stop timer */
}

/* schedule a video refresh in 'delay' ms */
static void schedule_refresh(VideoState *is, int delay)
{
    SDL_AddTimer(delay, sdl_refresh_timer_cb, is);
}

void video_display(VideoState *is)
{

    SDL_Rect rect;
    VideoPicture *vp;
    //AVPicture pict;
    float aspect_ratio;
    int w, h, x, y;

    vp = &is->pictq[is->pictq_rindex];
    if(vp->bmp)
    {
        if(is->video_st->codec->sample_aspect_ratio.num == 0)
        {
            aspect_ratio = 0;
        } else {
            aspect_ratio = av_q2d(is->video_st->codec->sample_aspect_ratio) *
                is->video_st->codec->width / is->video_st->codec->height;
        }
        if(aspect_ratio <= 0.0)
        {
            aspect_ratio = (float)is->video_st->codec->width /
                (float)is->video_st->codec->height;
        }
        h = screen->h;
        w = ((int)rint(h * aspect_ratio)) & -3;
        if(w > screen->w)
        {
            w = screen->w;
            h = ((int)rint(w / aspect_ratio)) & -3;
        }
        x = (screen->w - w) / 2;
        y = (screen->h - h) / 2;

        rect.x = x;
        rect.y = y;
        rect.w = w;
        rect.h = h;
        SDL_DisplayYUVOverlay(vp->bmp, &rect);
    }
}

void video_refresh_timer(void *userdata)
{
    VideoState *is = (VideoState *)userdata;
    VideoPicture __attribute__ ((unused))*vp;

    if(is->video_st)
    {
        if(is->pictq_size == 0)
            schedule_refresh(is, 1);
        else
        {
            vp = &is->pictq[is->pictq_rindex];
            /* Now, normally here goes a ton of code
               about timing, etc. we're just going to
               guess at a delay for now. You can
               increase and decrease this value and hard code
               the timing - but I don't suggest that ;)
               We'll learn how to do it for real later.
               */
            schedule_refresh(is, 80);

            /* show the */
            video_display(is);

            /* update queue for next */
            if(++is->pictq_rindex == VIDEO_PICTURE_QUEUE_SIZE)
            {
                is->pictq_rindex = 0;
            }
            SDL_LockMutex(is->pictq_mutex);
            is->pictq_size--;
            SDL_CondSignal(is->pictq_cond);
            SDL_UnlockMutex(is->pictq_mutex);
        }
    } else {
        schedule_refresh(is, 100);
    }
}

void alloc_picture(void *userdata) {

    VideoState *is = (VideoState *)userdata;
    VideoPicture *vp;

    vp = &is->pictq[is->pictq_windex];
    if(vp->bmp) {
        // we already have one make another, bigger/smaller
        SDL_FreeYUVOverlay(vp->bmp);
    }
    // Allocate a place to put our YUV image on that screen
    vp->bmp = SDL_CreateYUVOverlay(is->video_st->codec->width,
            is->video_st->codec->height,
            SDL_YV12_OVERLAY,
            screen);
    vp->width = is->video_st->codec->width;
    vp->height = is->video_st->codec->height;

    SDL_LockMutex(is->pictq_mutex);
    vp->allocated = 1;
    SDL_CondSignal(is->pictq_cond);
    SDL_UnlockMutex(is->pictq_mutex);

}

int queue_picture(VideoState *is, AVFrame *pFrame)
{
    VideoPicture *vp;
    int __attribute__ ((unused)) dst_pix_fmt;
    AVPicture pict;

    /* wait until we have space for a new pic */
    SDL_LockMutex(is->pictq_mutex);
    while(is->pictq_size >= VIDEO_PICTURE_QUEUE_SIZE && !is->quit)
        SDL_CondWait(is->pictq_cond, is->pictq_mutex);

    SDL_UnlockMutex(is->pictq_mutex);

    if(is->quit)
        return -1;

    // windex is set to 0 initially
    vp = &is->pictq[is->pictq_windex];

    /* allocate or resize the */
    if(!vp->bmp || vp->width != is->video_st->codec->width ||
            vp->height != is->video_st->codec->height) {
        SDL_Event event;

        vp->allocated = 0;
        /* we have to do it in the main thread */
        event.type = FF_ALLOC_EVENT;
        event.user.data1 = is;
        SDL_PushEvent(&event);

        /* wait until we have a picture allocated */
        SDL_LockMutex(is->pictq_mutex);
        while(!vp->allocated && !is->quit)
            SDL_CondWait(is->pictq_cond, is->pictq_mutex);

        SDL_UnlockMutex(is->pictq_mutex);
        if(is->quit)
            return -1;
    }
    /* We have a place to put our picture on the queue */

    if(vp->bmp)
    {
        SDL_LockYUVOverlay(vp->bmp);
        dst_pix_fmt = PIX_FMT_YUV420P;

        /* point pict at the queue */
        pict.data[0] = vp->bmp->pixels[0];
        pict.data[1] = vp->bmp->pixels[2];
        pict.data[2] = vp->bmp->pixels[1];

        pict.linesize[0] = vp->bmp->pitches[0];
        pict.linesize[1] = vp->bmp->pitches[2];
        pict.linesize[2] = vp->bmp->pitches[1];

        // Convert the image into YUV format that SDL uses
        //img_convert(&pict, dst_pix_fmt,
        // (AVPicture *)pFrame, is->video_st->codec->pix_fmt,
        // is->video_st->codec->width, is->video_st->codec->height);
        struct SwsContext *img_convert_ctx;
        img_convert_ctx = sws_getContext(is->video_st->codec->width,is->video_st->codec->height, is->video_st->codec->pix_fmt, is->video_st->codec->width, is->video_st->codec->height, PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);
        if(img_convert_ctx == NULL)
        {
            fprintf(stderr, "Cannot initialize the conversion context!\n");
            exit(1);
        }

        sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, is->video_st->codec->height, pict.data, pict.linesize);

        SDL_UnlockYUVOverlay(vp->bmp);
        /* now we inform our display thread that we have a pic ready */
        if(++is->pictq_windex == VIDEO_PICTURE_QUEUE_SIZE)
            is->pictq_windex = 0;
        SDL_LockMutex(is->pictq_mutex);
        is->pictq_size++;
        SDL_UnlockMutex(is->pictq_mutex);
    }
    return 0;
}

int video_thread(void *arg)
{
    VideoState *is = (VideoState *)arg;
    AVPacket pkt1, *packet = &pkt1;
    int __attribute__ ((unused)) len1, frameFinished;
    AVFrame *pFrame;

    pFrame = avcodec_alloc_frame();

    for(;;)
    {
        if(packet_queue_get(&is->videoq, packet, 1) < 0) // means we quit getting packets
            break;
        // Decode video frame
        len1 = avcodec_decode_video2(is->video_st->codec, pFrame, &frameFinished, packet);

        // Did we get a video frame?
        if(frameFinished)
        {
            if(queue_picture(is, pFrame) < 0)
                break;
        }
        av_free_packet(packet);
    }
    av_free(pFrame);
    return 0;
}

int stream_component_open(VideoState *is, int stream_index)
{
    AVFormatContext *pFormatCtx = is->pFormatCtx;
    AVCodecContext *codecCtx;
    AVCodec *codec;
    SDL_AudioSpec wanted_spec, spec;

    if(stream_index < 0 || stream_index >= pFormatCtx->nb_streams)
        return -1;

    // Get a pointer to the codec context for the video stream
    codecCtx = pFormatCtx->streams[stream_index]->codec;

    if(codecCtx->codec_type == AVMEDIA_TYPE_AUDIO)
    {
        // Set audio settings from codec info
        wanted_spec.freq = codecCtx->sample_rate;
        wanted_spec.format = AUDIO_S16SYS;
        wanted_spec.channels = codecCtx->channels;
        wanted_spec.silence = 0;
        wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE;
        wanted_spec.callback = audio_callback;
        wanted_spec.userdata = is;

        if(SDL_OpenAudio(&wanted_spec, &spec) < 0)
        {
            fprintf(stderr, "SDL_OpenAudio: %s\n", SDL_GetError());
            return -1;
        }
    }
    codec = avcodec_find_decoder(codecCtx->codec_id);
    if(!codec || (avcodec_open2(codecCtx, codec, NULL) < 0))
    {
        fprintf(stderr, "Unsupported codec!\n");
        return -1;
    }

    switch(codecCtx->codec_type)
    {
        case AVMEDIA_TYPE_AUDIO:
            is->audioStream = stream_index;
            is->audio_st = pFormatCtx->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;
        case AVMEDIA_TYPE_VIDEO:
            is->videoStream = stream_index;
            is->video_st = pFormatCtx->streams[stream_index];
            packet_queue_init(&is->videoq);
            is->video_tid = SDL_CreateThread(video_thread, is);
            break;
        default:
            break;
    }
    return 0;
}

int decode_interrupt_cb(void)
{
    return (global_video_state && global_video_state->quit);
}

int decode_thread(void *arg)
{

    VideoState *is = (VideoState *)arg;
    AVFormatContext *pFormatCtx;
    AVPacket pkt1, *packet = &pkt1;

    int video_index = -1;
    int audio_index = -1;
    int i;

    is->videoStream=-1;
    is->audioStream=-1;

    global_video_state = is;
    // will interrupt blocking functions if we
    //url_set_interrupt_cb(decode_interrupt_cb);

    pFormatCtx = avformat_alloc_context();
    // Open video file
    if(avformat_open_input(&pFormatCtx, is->filename, NULL, NULL)!=0)
        return -1; // Couldn't open file

    is->pFormatCtx = pFormatCtx;

    // Retrieve stream information
    if(avformat_find_stream_info(pFormatCtx, NULL)<0)
        return -1; // Couldn't find stream information

    // Dump information about file onto standard error
    av_dump_format(pFormatCtx, 0, is->filename, 0);

    // Find the first video stream

    for(i=0; i<pFormatCtx->nb_streams; i++)
    {
        if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO && video_index < 0)
            video_index=i;
        if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_AUDIO && audio_index < 0)
            audio_index=i;
    }
    if(audio_index >= 0)
        stream_component_open(is, audio_index);
    if(video_index >= 0)
        stream_component_open(is, video_index);

    if(is->videoStream < 0 || is->audioStream < 0)
    {
        fprintf(stderr, "%s: could not open codecs\n", is->filename);
        goto fail;
    }

    // main decode loop

    for(;;)
    {
        if(is->quit)
            break;
        // seek stuff goes here
        if(is->audioq.size > MAX_AUDIOQ_SIZE || is->videoq.size > MAX_VIDEOQ_SIZE)
        {
            SDL_Delay(10);
            continue;
        }
        if(av_read_frame(is->pFormatCtx, packet) < 0)
        {
            //if(url_ferror(&pFormatCtx->pb) == 0)
            if(pFormatCtx->pb&&pFormatCtx->pb->error)
            {
                SDL_Delay(100); /* no error; wait for user input */
                continue;
            } else {
                break;
            }
        }
        // Is this a packet from the video stream?
        if(packet->stream_index == is->videoStream)
            packet_queue_put(&is->videoq, packet);
        else if(packet->stream_index == is->audioStream)
            packet_queue_put(&is->audioq, packet);
        else
            av_free_packet(packet);
    }
    /* all done - wait for it */
    while(!is->quit)
        SDL_Delay(100);

fail:
    if(1){
        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 = av_mallocz(sizeof(VideoState));

    if(argc < 2)
    {
        fprintf(stderr, "Usage: test \n");
        exit(1);
    }
    // Register all formats and codecs
    av_register_all();

    if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER))
    {
        fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError());
        exit(1);
    }

    // Make a screen to put our video
#ifndef __DARWIN__
    screen = SDL_SetVideoMode(640, 480, 0, 0);
#else
    screen = SDL_SetVideoMode(640, 480, 24, 0);
#endif
    if(!screen)
    {
        fprintf(stderr, "SDL: could not set video mode - exiting\n");
        exit(1);
    }

    //void pstrcpy(char *dst, size_t size, const char *src)
    //pstrcpy(is->filename, sizeof(is->filename), argv[1]);

    //size_t av_strlcpy(char *dst, const char *src, size_t size)
    av_strlcpy(is->filename, argv[1], sizeof(is->filename));

    is->pictq_mutex = SDL_CreateMutex();
    is->pictq_cond = SDL_CreateCond();

    schedule_refresh(is, 40);

    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:
                is->quit = 1;
                SDL_Quit();
                return 0;
                break;
            case FF_ALLOC_EVENT:
                alloc_picture(event.user.data1);
                break;
            case FF_REFRESH_EVENT:
                video_refresh_timer(event.user.data1);
                break;
            default:
                break;
        }
    }
    return 0;
}

2. Makefile

CC=gcc
CFLAGS = -Wall -g -I/home/sun/code/ffmpeg-1.0/install/include/ -I/home/sun/code/SDL-1.2.15/install/include/SDL/
LDFLAGS = -L/home/sun/code/ffmpeg-1.0/install/lib/ -lavutil -lavformat -lavcodec -lavutil -lm -lswscale
LDFLAGS += -L/home/sun/code/SDL-1.2.15/install/lib/ -lSDLmain -lSDL

TARGETS=4spawning
all: $(TARGETS)
4spawning.o:4spawning.c
    $(CC) $(CFLAGS) -o $@ -c $^

4spawning:4spawning.o
    $(CC) -o $@ $^ $(LDFLAGS)
clean:
    rm -rf *.o  $(TARGETS)