// tutorial05.c

// A pedagogical video player that really works!

//

// 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

// tutorial05 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 <SDL.h>

#include <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 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;

double pts;

} VideoPicture;

typedef struct VideoState {

AVFormatContext *pFormatCtx;

int videoStream, audioStream;

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 frame_timer;

double frame_last_pts;

double frame_last_delay;

double video_clock; ///<pts of last decoded frame / predicted pts of next decoded frame

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;

} 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;

}

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;

}

int audio_decode_frame(VideoState *is, double *pts_ptr) {

int len1, data_size = 0, n;

AVPacket *pkt = &is->audio_pkt;

double pts;

for(;;) {

while(is->audio_pkt_size > 0) {

int got_frame;

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

);

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

}

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;

is->audio_clock += (double)data_size /

(double)(n * is->audio_st->codec->sample_rate);

/* We have data, return it and come back for more later */

return data_size;

}

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;

}

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 {

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];

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 */

ref_clock = get_audio_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;

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);

/* 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 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;

}

void our_release_buffer(struct AVCodecContext *c, AVFrame *pic) {

if(pic) av_freep(&pic->opaque);

avcodec_default_release_buffer(c, pic);

}

int video_thread(void *arg) {

VideoState *is = (VideoState *)arg;

AVPacket pkt1, *packet = &pkt1;

int frameFinished;

AVFrame *pFrame;

double pts;

pFrame = av_frame_alloc();

for(;;) {

if(packet_queue_get(&is->videoq, packet, 1) < 0) {

// means we quit getting packets

break;

}

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;

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;

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_buffer2 = our_get_buffer;

codecCtx->release_buffer = our_release_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;

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;

}

// 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(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;

}

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

SDL_Event event;

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->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;

/*

* 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;

}