tutorial07.c

// tutorial07.c
// A pedagogical video player that really works! Now with seeking features.
//
// This tutorial was written by Stephen Dranger (dranger@gmail.com).
//
// Code based on FFplay, Copyright (c) 2003 Fabrice Bellard,
// and a tutorial by Martin Bohme (boehme@inb.uni-luebeckREMOVETHIS.de)
// Tested on Gentoo, CVS version 5/01/07 compiled with GCC 4.1.1
//
// Use the Makefile to build all the samples.
//
// Run using
// tutorial07 myvideofile.mpg
//
// to play the video.

#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libavformat/avio.h>
#include <libswscale/swscale.h>
#include <libavutil/avstring.h>
#include <libavutil/time.h>
#include <libavutil/mathematics.h>

#ifdef __RESAMPLER__
#include <libavutil/opt.h>

#ifdef __LIBAVRESAMPLE__
#include <libavresample/avresample.h>
#endif

#ifdef __LIBSWRESAMPLE__
#include <libswresample/swresample.h>
#endif
#endif

#include <SDL/SDL.h>
#include <SDL/SDL_thread.h>
#ifdef __MINGW32__
#undef main /* Prevents SDL from overriding main() */
#endif
#include <stdio.h>
#include <math.h>

#define SDL_AUDIO_BUFFER_SIZE 1024
#define MAX_AUDIO_FRAME_SIZE 192000
#define MAX_AUDIOQ_SIZE (5 * 16 * 1024)
#define MAX_VIDEOQ_SIZE (5 * 256 * 1024)
#define AV_SYNC_THRESHOLD 0.01
#define AV_NOSYNC_THRESHOLD 10.0
#define SAMPLE_CORRECTION_PERCENT_MAX 10
#define AUDIO_DIFF_AVG_NB 20
#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
#define DEFAULT_AV_SYNC_TYPE AV_SYNC_VIDEO_MASTER

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;
    double pts;
} VideoPicture;

typedef struct VideoState {
    AVFormatContext *pFormatCtx;
    int             videoStream, audioStream;

    int             av_sync_type;
    double          external_clock; /* external clock base */
    int64_t         external_clock_time;
    int             seek_req;
    int             seek_flags;
    int64_t         seek_pos;

    double          audio_clock;
    AVStream        *audio_st;
    PacketQueue     audioq;
    AVFrame         audio_frame;
    uint8_t         audio_buf[(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;
    int             audio_hw_buf_size;
    double          audio_diff_cum; /* used for AV difference average computation */
    double          audio_diff_avg_coef;
    double          audio_diff_threshold;
    int             audio_diff_avg_count;
    uint8_t         audio_need_resample;
    double          frame_timer;
    double          frame_last_pts;
    double          frame_last_delay;
    double          video_clock; ///<pts of last decoded frame / predicted pts of next decoded frame
    double          video_current_pts; ///<current displayed pts (different from video_clock if frame fifos are used)
    int64_t         video_current_pts_time;  ///<time (av_gettime) at which we updated video_current_pts - used to have running video pts
    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;

    AVIOContext     *io_context;
    struct SwsContext *sws_ctx;

#ifdef __RESAMPLER__
#ifdef __LIBAVRESAMPLE__
    AVAudioResampleContext *pSwrCtx;
#endif

#ifdef __LIBSWRESAMPLE__
    SwrContext *pSwrCtx;
#endif
    uint8_t *pResampledOut;
    int resample_lines;
    uint64_t resample_size;
#endif

} VideoState;

enum {
    AV_SYNC_AUDIO_MASTER,
    AV_SYNC_VIDEO_MASTER,
    AV_SYNC_EXTERNAL_MASTER,
};

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;
AVPacket flush_pkt;

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(pkt != &flush_pkt && 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;
}

static void packet_queue_flush(PacketQueue *q) {
    AVPacketList *pkt, *pkt1;

    SDL_LockMutex(q->mutex);

    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);
}

double get_audio_clock(VideoState *is) {
    double pts;
    int hw_buf_size, bytes_per_sec, n;

    pts = is->audio_clock; /* maintained in the audio thread */
    hw_buf_size = is->audio_buf_size - is->audio_buf_index;
    bytes_per_sec = 0;
    n = is->audio_st->codec->channels * 2;

    if(is->audio_st) {
        bytes_per_sec = is->audio_st->codec->sample_rate * n;
    }

    if(bytes_per_sec) {
        pts -= (double)hw_buf_size / bytes_per_sec;
    }

    return pts;
}

double get_video_clock(VideoState *is) {
    double delta;

    delta = (av_gettime() - is->video_current_pts_time) / 1000000.0;
    return is->video_current_pts + delta;
}

double get_external_clock(VideoState *is) {
    return av_gettime() / 1000000.0;
}

double get_master_clock(VideoState *is) {
    if(is->av_sync_type == AV_SYNC_VIDEO_MASTER) {
        return get_video_clock(is);

    } else if(is->av_sync_type == AV_SYNC_AUDIO_MASTER) {
        return get_audio_clock(is);

    } else {
        return get_external_clock(is);
    }
}

/* Add or subtract samples to get a better sync, return new
   audio buffer size */

int synchronize_audio(VideoState *is, short *samples,
                      int samples_size, double pts) {
    int n;
    double ref_clock;

    n = 2 * is->audio_st->codec->channels;

    if(is->av_sync_type != AV_SYNC_AUDIO_MASTER) {
        double diff, avg_diff;
        int wanted_size, min_size, max_size /*, nb_samples */;

        ref_clock = get_master_clock(is);
        diff = get_audio_clock(is) - ref_clock;

        if(diff < AV_NOSYNC_THRESHOLD) {
            // accumulate the diffs
            is->audio_diff_cum = diff + is->audio_diff_avg_coef
                                 * is->audio_diff_cum;

            if(is->audio_diff_avg_count < AUDIO_DIFF_AVG_NB) {
                is->audio_diff_avg_count++;

            } else {
                avg_diff = is->audio_diff_cum * (1.0 - is->audio_diff_avg_coef);

                if(fabs(avg_diff) >= is->audio_diff_threshold) {
                    wanted_size = samples_size + ((int)(diff * is->audio_st->codec->sample_rate) * n);
                    min_size = samples_size * ((100 - SAMPLE_CORRECTION_PERCENT_MAX) / 100);
                    max_size = samples_size * ((100 + SAMPLE_CORRECTION_PERCENT_MAX) / 100);

                    if(wanted_size < min_size) {
                        wanted_size = min_size;

                    } else if(wanted_size > max_size) {
                        wanted_size = max_size;
                    }

                    if(wanted_size < samples_size) {
                        /* remove samples */
                        samples_size = wanted_size;

                    } else if(wanted_size > samples_size) {
                        uint8_t *samples_end, *q;
                        int nb;

                        /* add samples by copying final sample*/
                        nb = (samples_size - wanted_size);
                        samples_end = (uint8_t *)samples + samples_size - n;
                        q = samples_end + n;

                        while(nb > 0) {
                            memcpy(q, samples_end, n);
                            q += n;
                            nb -= n;
                        }

                        samples_size = wanted_size;
                    }
                }
            }

        } else {
            /* difference is TOO big; reset diff stuff */
            is->audio_diff_avg_count = 0;
            is->audio_diff_cum = 0;
        }
    }

    return samples_size;
}

long audio_tutorial_resample(VideoState *is, struct AVFrame *inframe) {

#ifdef __RESAMPLER__

#ifdef __LIBAVRESAMPLE__

// There is pre 1.0 libavresample and then there is above..
#if LIBAVRESAMPLE_VERSION_MAJOR == 0
    void **resample_input_bytes = (void **)inframe->extended_data;
#else
    uint8_t **resample_input_bytes = (uint8_t **)inframe->extended_data;
#endif

#else
    uint8_t **resample_input_bytes = (uint8_t **)inframe->extended_data;
#endif


    int resample_nblen = 0;
    long resample_long_bytes = 0;

    if( is->pResampledOut == NULL || inframe->nb_samples > is->resample_size) {
        
#if __LIBAVRESAMPLE__
        is->resample_size = av_rescale_rnd(avresample_get_delay(is->pSwrCtx) +
                                           inframe->nb_samples,
                                           44100,
                                           44100,
                                           AV_ROUND_UP);
#else
        is->resample_size = av_rescale_rnd(swr_get_delay(is->pSwrCtx,
                                           44100) +
                                           inframe->nb_samples,
                                           44100,
                                           44100,
                                           AV_ROUND_UP);
#endif

        if(is->pResampledOut != NULL) {
            av_free(is->pResampledOut);
            is->pResampledOut = NULL;
        }

        av_samples_alloc(&is->pResampledOut, &is->resample_lines, 2, is->resample_size,
                         AV_SAMPLE_FMT_S16, 0);

    }


#ifdef __LIBAVRESAMPLE__

// OLD API (0.0.3) ... still NEW API (1.0.0 and above).. very frustrating..
// USED IN FFMPEG 1.0 (LibAV SOMETHING!). New in FFMPEG 1.1 and libav 9
#if LIBAVRESAMPLE_VERSION_INT <= 3
    // AVResample OLD
    resample_nblen = avresample_convert(is->pSwrCtx, (void **)&is->pResampledOut, 0,
                                        is->resample_size,
                                        (void **)resample_input_bytes, 0, inframe->nb_samples);
#else
    //AVResample NEW
    resample_nblen = avresample_convert(is->pSwrCtx, (uint8_t **)&is->pResampledOut,
                                        0, is->resample_size,
                                        (uint8_t **)resample_input_bytes, 0, inframe->nb_samples);
#endif

#else
    // SWResample
    resample_nblen = swr_convert(is->pSwrCtx, (uint8_t **)&is->pResampledOut,
                                 is->resample_size,
                                 (const uint8_t **)resample_input_bytes, inframe->nb_samples);
#endif

    resample_long_bytes = av_samples_get_buffer_size(NULL, 2, resample_nblen,
                         AV_SAMPLE_FMT_S16, 1);

    if (resample_nblen < 0) {
        fprintf(stderr, "reSample to another sample format failed!\n");
        return -1;
    }

    return resample_long_bytes;

#else
    return -1;
#endif
}

int audio_decode_frame(VideoState *is, double *pts_ptr) {
    /* For example with wma audio package size can be
       like 100 000 bytes */
    long len1, data_size = 0;
    AVPacket *pkt = &is->audio_pkt;
    double pts;
    int n = 0;
#ifdef __RESAMPLER__
    long resample_size = 0;
#endif

    for(;;) {
        while(is->audio_pkt_size > 0) {
            int got_frame = 0;
            len1 = avcodec_decode_audio4(is->audio_st->codec, &is->audio_frame, &got_frame, pkt);

            if(len1 < 0) {
                /* if error, skip frame */
                is->audio_pkt_size = 0;
                break;
            }

            if(got_frame) {
                data_size =
                    av_samples_get_buffer_size
                    (
                        NULL,
                        is->audio_st->codec->channels,
                        is->audio_frame.nb_samples,
                        is->audio_st->codec->sample_fmt,
                        1
                    );

#ifdef __RESAMPLER__

                if(is->audio_need_resample == 1) {
                    resample_size = audio_tutorial_resample(is, &is->audio_frame);

                    if( resample_size > 0 ) {
                        memcpy(is->audio_buf, is->pResampledOut, resample_size);
                        memset(is->pResampledOut, 0x00, resample_size);
                    }

                } else {
#endif

                    memcpy(is->audio_buf, is->audio_frame.data[0], data_size);
#ifdef __RESAMPLER__
                }

#endif
            }

            is->audio_pkt_data += len1;
            is->audio_pkt_size -= len1;

            if(data_size <= 0) {
                /* No data yet, get more frames */
                continue;
            }

            pts = is->audio_clock;
            *pts_ptr = pts;
            n = 2 * is->audio_st->codec->channels;

#ifdef __RESAMPLER__

            /* If you just return original data_size you will suffer
               for clicks because you don't have that much data in
               queue incoming so return resampled size. */
            if(is->audio_need_resample == 1) {
                is->audio_clock += (double)resample_size /
                                   (double)(n * is->audio_st->codec->sample_rate);
                return resample_size;

            } else {
#endif
                /* We have data, return it and come back for more later */
                is->audio_clock += (double)data_size /
                                   (double)(n * is->audio_st->codec->sample_rate);
                return data_size;
#ifdef __RESAMPLER__
            }

#endif
        }

        if(pkt->data) {
            av_free_packet(pkt);
        }

        if(is->quit) {
            return -1;
        }

        /* next packet */
        if(packet_queue_get(&is->audioq, pkt, 1) < 0) {
            return -1;
        }

        if(pkt->data == flush_pkt.data) {
            avcodec_flush_buffers(is->audio_st->codec);
            continue;
        }

        is->audio_pkt_data = pkt->data;
        is->audio_pkt_size = pkt->size;

        /* if update, update the audio clock w/pts */
        if(pkt->pts != AV_NOPTS_VALUE) {
            is->audio_clock = av_q2d(is->audio_st->time_base) * pkt->pts;
        }
    }
}

void audio_callback(void *userdata, Uint8 *stream, int len) {

    VideoState *is = (VideoState *)userdata;
    int len1, audio_size;
    double pts;

    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(is, &pts);

            if(audio_size < 0) {
                /* If error, output silence */
                is->audio_buf_size = 1024;
                memset(is->audio_buf, 0, is->audio_buf_size);

            } else {
                audio_size = synchronize_audio(is, (int16_t *)is->audio_buf,
                                               audio_size, pts);
                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;
    //int i;

    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 *vp;
    double actual_delay, delay, sync_threshold, ref_clock, diff;

    if(is->video_st) {
        if(is->pictq_size == 0) {
            schedule_refresh(is, 1);

        } else {
            vp = &is->pictq[is->pictq_rindex];

            is->video_current_pts = vp->pts;
            is->video_current_pts_time = av_gettime();

            delay = vp->pts - is->frame_last_pts; /* the pts from last time */

            if(delay <= 0 || delay >= 1.0) {
                /* if incorrect delay, use previous one */
                delay = is->frame_last_delay;
            }

            /* save for next time */
            is->frame_last_delay = delay;
            is->frame_last_pts = vp->pts;

            /* update delay to sync to audio if not master source */
            if(is->av_sync_type != AV_SYNC_VIDEO_MASTER) {
                ref_clock = get_master_clock(is);
                diff = vp->pts - ref_clock;

                /* Skip or repeat the frame. Take delay into account
                   FFPlay still doesn't "know if this is the best guess." */
                sync_threshold = (delay > AV_SYNC_THRESHOLD) ? delay : AV_SYNC_THRESHOLD;

                if(fabs(diff) < AV_NOSYNC_THRESHOLD) {
                    if(diff <= -sync_threshold) {
                        delay = 0;

                    } else if(diff >= sync_threshold) {
                        delay = 2 * delay;
                    }
                }
            }

            is->frame_timer += delay;
            /* computer the REAL delay */
            actual_delay = is->frame_timer - (av_gettime() / 1000000.0);

            if(actual_delay < 0.010) {
                /* Really it should skip the picture instead */
                actual_delay = 0.010;
            }

            schedule_refresh(is, (int)(actual_delay * 1000 + 0.5));

            /* show the picture! */
            video_display(is);

            /* update queue for next picture! */
            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, double pts) {

    VideoPicture *vp;
    //int 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 buffer! */
    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 we are skipping a frame, do we set this to null
       but still return vp->allocated = 1? */


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

        SDL_UnlockYUVOverlay(vp->bmp);
        vp->pts = pts;

        /* 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;
}

double synchronize_video(VideoState *is, AVFrame *src_frame, double pts) {

    double frame_delay;

    if(pts != 0) {
        /* if we have pts, set video clock to it */
        is->video_clock = pts;

    } else {
        /* if we aren't given a pts, set it to the clock */
        pts = is->video_clock;
    }

    /* update the video clock */
    frame_delay = av_q2d(is->video_st->codec->time_base);
    /* if we are repeating a frame, adjust clock accordingly */
    frame_delay += src_frame->repeat_pict * (frame_delay * 0.5);
    is->video_clock += frame_delay;
    return pts;
}

uint64_t global_video_pkt_pts = AV_NOPTS_VALUE;

/* These are called whenever we allocate a frame
 * buffer. We use this to store the global_pts in
 * a frame at the time it is allocated.
 */

int our_get_buffer(struct AVCodecContext *c, AVFrame *pic, int flags) {
    int ret = avcodec_default_get_buffer(c, pic);
    uint64_t *pts = av_malloc(sizeof(uint64_t));
    *pts = global_video_pkt_pts;
    pic->opaque = pts;
    return ret;
}

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

    pFrame = avcodec_alloc_frame();

    for(;;) {
        if(packet_queue_get(&is->videoq, packet, 1) < 0) {
            // means we quit getting packets
            break;
        }

        if(packet->data == flush_pkt.data) {
            avcodec_flush_buffers(is->video_st->codec);
            continue;
        }

        pts = 0;

        // Save global pts to be stored in pFrame in first call
        global_video_pkt_pts = packet->pts;
        // Decode video frame
        avcodec_decode_video2(is->video_st->codec, pFrame, &frameFinished,
                              packet);

        if(packet->dts == AV_NOPTS_VALUE
                && pFrame->opaque && *(uint64_t*)pFrame->opaque != AV_NOPTS_VALUE) {
            pts = *(uint64_t *)pFrame->opaque;

        } else if(packet->dts != AV_NOPTS_VALUE) {
            pts = packet->dts;

        } else {
            pts = 0;
        }

        pts *= av_q2d(is->video_st->time_base);

        // Did we get a video frame?
        if(frameFinished) {
            pts = synchronize_video(is, pFrame, pts);

            if(queue_picture(is, pFrame, pts) < 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 = NULL;
    AVCodec *codec = NULL;
    AVDictionary *optionsDict = NULL;
    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;
        }

        is->audio_hw_buf_size = spec.size;
    }

    codec = avcodec_find_decoder(codecCtx->codec_id);

    if(!codec || (avcodec_open2(codecCtx, codec, &optionsDict) < 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;

            /* averaging filter for audio sync */
            is->audio_diff_avg_coef = exp(log(0.01 / AUDIO_DIFF_AVG_NB));
            is->audio_diff_avg_count = 0;
            /* Correct audio only if larger error than this */
            is->audio_diff_threshold = 2.0 * SDL_AUDIO_BUFFER_SIZE / codecCtx->sample_rate;

            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];

            is->frame_timer = (double)av_gettime() / 1000000.0;
            is->frame_last_delay = 40e-3;
            is->video_current_pts_time = av_gettime();

            packet_queue_init(&is->videoq);
            is->video_tid = SDL_CreateThread(video_thread, is);
            is->sws_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_BILINEAR,
                    NULL,
                    NULL,
                    NULL
                );
            codecCtx->get_buffer = our_get_buffer;

            break;

        default:
            break;
    }

    return 0;
}

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

int decode_thread(void *arg) {

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

    AVDictionary *io_dict = NULL;
    AVIOInterruptCB callback;

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

    is->videoStream = -1;
    is->audioStream = -1;
    is->audio_need_resample = 0;

    global_video_state = is;
    // will interrupt blocking functions if we quit!
    callback.callback = decode_interrupt_cb;
    callback.opaque = is;

    if(avio_open2(&is->io_context, is->filename, 0, &callback, &io_dict)) {
        fprintf(stderr, "Unable to open I/O for %s\n", is->filename);
        return -1;
    }

    // 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;
    }

#ifdef __RESAMPLER__

    if( audio_index >= 0
            && pFormatCtx->streams[audio_index]->codec->sample_fmt != AV_SAMPLE_FMT_S16) {
        is->audio_need_resample = 1;
        is->pResampledOut = NULL;
        is->pSwrCtx = NULL;

        printf("Configure resampler: ");

#ifdef __LIBAVRESAMPLE__
        printf("libAvResample\n");
        is->pSwrCtx = avresample_alloc_context();
#endif

#ifdef __LIBSWRESAMPLE__
        printf("libSwResample\n");
        is->pSwrCtx = swr_alloc();
#endif

        // Some MP3/WAV don't tell this so make assumtion that
        // They are stereo not 5.1
        if (pFormatCtx->streams[audio_index]->codec->channel_layout == 0
                && pFormatCtx->streams[audio_index]->codec->channels == 2) {
            pFormatCtx->streams[audio_index]->codec->channel_layout = AV_CH_LAYOUT_STEREO;

        } else if (pFormatCtx->streams[audio_index]->codec->channel_layout == 0
                   && pFormatCtx->streams[audio_index]->codec->channels == 1) {
            pFormatCtx->streams[audio_index]->codec->channel_layout = AV_CH_LAYOUT_MONO;

        } else if (pFormatCtx->streams[audio_index]->codec->channel_layout == 0
                   && pFormatCtx->streams[audio_index]->codec->channels == 0) {
            pFormatCtx->streams[audio_index]->codec->channel_layout = AV_CH_LAYOUT_STEREO;
            pFormatCtx->streams[audio_index]->codec->channels = 2;
        }

        av_opt_set_int(is->pSwrCtx, "in_channel_layout",
                       pFormatCtx->streams[audio_index]->codec->channel_layout, 0);
        av_opt_set_int(is->pSwrCtx, "in_sample_fmt",
                       pFormatCtx->streams[audio_index]->codec->sample_fmt, 0);
        av_opt_set_int(is->pSwrCtx, "in_sample_rate",
                       pFormatCtx->streams[audio_index]->codec->sample_rate, 0);

        av_opt_set_int(is->pSwrCtx, "out_channel_layout", AV_CH_LAYOUT_STEREO, 0);
        av_opt_set_int(is->pSwrCtx, "out_sample_fmt", AV_SAMPLE_FMT_S16, 0);
        av_opt_set_int(is->pSwrCtx, "out_sample_rate", 44100, 0);

#ifdef __LIBAVRESAMPLE__

        if (avresample_open(is->pSwrCtx) < 0) {
#else

        if (swr_init(is->pSwrCtx) < 0) {
#endif
            fprintf(stderr, " ERROR!! From Samplert: %d Hz Sample format: %s\n",
                    pFormatCtx->streams[audio_index]->codec->sample_rate,
                    av_get_sample_fmt_name(pFormatCtx->streams[audio_index]->codec->sample_fmt));
            fprintf(stderr, "         To 44100 Sample format: s16\n");
            is->audio_need_resample = 0;
            is->pSwrCtx = NULL;;
        }

    }

#endif

    // main decode loop

    for(;;) {
        if(is->quit) {
            break;
        }

        // seek stuff goes here
        if(is->seek_req) {
            int stream_index = -1;
            int64_t seek_target = is->seek_pos;

            if(is->videoStream >= 0) {
                stream_index = is->videoStream;

            } else if(is->audioStream >= 0) {
                stream_index = is->audioStream;
            }

            if(stream_index >= 0) {
                seek_target = av_rescale_q(seek_target, AV_TIME_BASE_Q, pFormatCtx->streams[stream_index]->time_base);
            }

            if(av_seek_frame(is->pFormatCtx, stream_index, seek_target, is->seek_flags) < 0) {
                fprintf(stderr, "%s: error while seeking\n", is->pFormatCtx->filename);

            } else {
                if(is->audioStream >= 0) {
                    packet_queue_flush(&is->audioq);
                    packet_queue_put(&is->audioq, &flush_pkt);
                }

                if(is->videoStream >= 0) {
                    packet_queue_flush(&is->videoq);
                    packet_queue_put(&is->videoq, &flush_pkt);
                }
            }

            is->seek_req = 0;
        }

        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(is->pFormatCtx->pb->error == 0) {
                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: {
        SDL_Event event;
        event.type = FF_QUIT_EVENT;
        event.user.data1 = is;
        SDL_PushEvent(&event);
    }
    return 0;
}

void stream_seek(VideoState *is, int64_t pos, int rel) {

    if(!is->seek_req) {
        is->seek_pos = pos;
        is->seek_flags = rel < 0 ? AVSEEK_FLAG_BACKWARD : 0;
        is->seek_req = 1;
    }
}

int main(int argc, char *argv[]) {

    SDL_Event       event;
    //double          pts;
    VideoState      *is;

    is = av_mallocz(sizeof(VideoState));

    if(argc < 2) {
        fprintf(stderr, "Usage: test <file>\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);
    }

    av_strlcpy(is->filename, argv[1], 1024);

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

    schedule_refresh(is, 40);

    is->av_sync_type = DEFAULT_AV_SYNC_TYPE;
    is->parse_tid = SDL_CreateThread(decode_thread, is);

    if(!is->parse_tid) {
        av_free(is);
        return -1;
    }

    av_init_packet(&flush_pkt);
    flush_pkt.data = (unsigned char *)"FLUSH";

    for(;;) {
        double incr, pos;
        SDL_WaitEvent(&event);

        switch(event.type) {
            case SDL_KEYDOWN:
                switch(event.key.keysym.sym) {
                    case SDLK_LEFT:
                        incr = -10.0;
                        goto do_seek;

                    case SDLK_RIGHT:
                        incr = 10.0;
                        goto do_seek;

                    case SDLK_UP:
                        incr = 60.0;
                        goto do_seek;

                    case SDLK_DOWN:
                        incr = -60.0;
                        goto do_seek;
do_seek:

                        if(global_video_state) {
                            pos = get_master_clock(global_video_state);
                            pos += incr;
                            stream_seek(global_video_state, (int64_t)(pos * AV_TIME_BASE), incr);
                        }

                        break;

                    default:
                        break;
                }

                break;

            case FF_QUIT_EVENT:
            case SDL_QUIT:
                is->quit = 1;
                /*
                 * If the video has finished playing, then both the picture and
                 * audio queues are waiting for more data.  Make them stop
                 * waiting and terminate normally.
                 */
                SDL_CondSignal(is->audioq.cond);
                SDL_CondSignal(is->videoq.cond);
                SDL_Quit();
                exit(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;
}