An ffmpeg and SDL turorial:FFMpeg 和 SDL程式設計參考,修改了原始碼已無錯誤執行

NO IMAGE

turorial 08原始碼。

原始程式碼沒有考慮視訊和顯示視窗大小不同的問題,會導致bug,

而自己又搞不明白到底是什麼情況。

我對原始碼做了一些修改,可以在VS上順利編譯通過並且無錯執行。

av_seek_frame可能存在一些問題,目前不太清楚為什麼經常出現錯誤

下面為修改好的原始碼,可以直接編譯:

// tutorial08.c
// A pedagogical video player that really works! Now with seeking features.
//
// Code based on FFplay, Copyright (c) 2003 Fabrice Bellard,
// and a tutorial by Martin Bohme ([email protected])
// Tested on Gentoo, CVS version 5/01/07 compiled with GCC 4.1.1
// Use
//
// gcc -o tutorial08 tutorial08.c -lavformat -lavcodec -lz -lm `sdl-config --cflags --libs`
// to build (assuming libavformat and libavcodec are correctly installed,
// and assuming you have sdl-config. Please refer to SDL docs for your installation.)
//
// Run using
// tutorial08 myvideofile.mpg
//
// to play the video.
// 2012-12-21 luofl 修改了因為視訊大小與建立的視窗大小不一致帶來的問題
// 解決方案是通過對視訊影象進行縮放以適應視窗大小,見下面的修改程式碼
#include "avcodec.h"
#include "avformat.h"
#include "SDL/SDL.h"
#include "SDL/SDL_thread.h"
#include "swscale.h"
#ifdef main
#undef main /* Prevents SDL from overriding main() */
#endif
#include <stdio.h>
#pragma comment(linker,"/NODEFAULTLIB:libc.lib")
#pragma comment(lib, "avcodec.lib")
#pragma comment(lib, "avdevice.lib")
#pragma comment(lib, "avfilter.lib")
#pragma comment(lib, "avformat.lib")
#pragma comment(lib, "swscale.lib")
#pragma comment(lib, "avutil.lib")
#pragma comment(lib, "postproc.lib")
#pragma comment(lib, "swresample.lib")
#pragma comment(lib, "SDL.lib")
#include <stdio.h>
#include <math.h>
#define SDL_AUDIO_BUFFER_SIZE 1024
#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;
DECLARE_ALIGNED(16, 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;
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;
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;
} 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;
long rint(double x) 
{ 
if(x >= 0.)
return (long)(x   0.5); 
else 
return (long)(x - 0.5); 
}
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;
}
int audio_decode_frame(VideoState *is, uint8_t *audio_buf, int buf_size, double *pts_ptr)
{
int len1, data_size, n;
AVPacket *pkt = &is->audio_pkt;
double pts;
for(;;)
{
while(is->audio_pkt_size > 0)
{
data_size = buf_size;
len1 = avcodec_decode_audio2(is->audio_st->codec,
(int16_t *)audio_buf, &data_size,
is->audio_pkt_data, is->audio_pkt_size);
if(len1 < 0)
{
/* if error, skip frame */
is->audio_pkt_size = 0;
break;
}
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;
}
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, is->audio_buf, sizeof(is->audio_buf), &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;
}
// apparently this assumption is bad
#if 0
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;
#else
rect.x = 0;
rect.y = 0;
rect.w = screen->w;
rect.h = screen->h;
#endif
SDL_LockYUVOverlay(vp->bmp);
SDL_DisplayYUVOverlay(vp->bmp, &rect);
SDL_UnlockYUVOverlay(vp->bmp);
}
}
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
#if 1
// 修改:這裡按照視窗大小建立顯示層,而不是根據視訊的大小
vp->bmp = SDL_CreateYUVOverlay(screen->w,	// is->video_st->codec->width,	
screen->h, //	is->video_st->codec->height,
#else
vp->bmp = SDL_CreateYUVOverlay(is->video_st->codec->width,	
is->video_st->codec->height,
#endif
SDL_YV12_OVERLAY,// SDL_IYUV_OVERLAY、SDL_YV12_OVERLAY
screen);
#if 0
vp->width = is->video_st->codec->width;
vp->height = is->video_st->codec->height;
#else
vp->width = screen->w;
vp->height = screen->h;
#endif
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;
static struct SwsContext *img_convert_ctx;
/* 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.data[3] = NULL;
pict.linesize[0] = vp->bmp->pitches[0];
pict.linesize[1] = vp->bmp->pitches[2];
pict.linesize[2] = vp->bmp->pitches[1];
pict.linesize[3] = 0;
// Convert the image into YUV format that SDL uses
if(img_convert_ctx == NULL)
{
int w = is->video_st->codec->width;
int h = is->video_st->codec->height;
img_convert_ctx = sws_getContext(w, h,
is->video_st->codec->pix_fmt, 
screen->w, screen->h,	// 修改:同樣這裡按照視窗大小建立顯示層,而不是根據視訊的大小
dst_pix_fmt, 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, 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 len1, 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
global_video_pkt_pts = packet->pts;
// Decode video frame
len1 = avcodec_decode_video(is->video_st->codec, pFrame, &frameFinished,
packet->data, packet->size);
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;
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 == CODEC_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_open(codecCtx, codec) < 0))
{
fprintf(stderr, "Unsupported codec!\n");
return -1;
}
switch(codecCtx->codec_type)
{
case CODEC_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 CODEC_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);
codecCtx->get_buffer = our_get_buffer;
codecCtx->release_buffer = our_release_buffer;
break;
default:
break;
}
}
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 quit!
url_set_interrupt_cb(decode_interrupt_cb);
// Open video file
if(av_open_input_file(&pFormatCtx, is->filename, NULL, 0, NULL) != 0)
return -1; // Couldn't open file
is->pFormatCtx = pFormatCtx;
// Retrieve stream information
if(av_find_stream_info(pFormatCtx) < 0)
return -1; // Couldn't find stream information
// Dump information about file onto standard error
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 == CODEC_TYPE_VIDEO &&
video_index < 0)
{
video_index = i;
}
if(pFormatCtx->streams[i]->codec->codec_type == CODEC_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->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)
{
AVRational avRation = {1, AV_TIME_BASE};
seek_target = av_rescale_q(seek_target, avRation, pFormatCtx->streams[stream_index]->time_base);
}
if(!av_seek_frame(is->pFormatCtx, stream_index, seek_target, is->seek_flags))
{
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(url_ferror(&pFormatCtx->pb) == 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          pos;
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
// 修改:這裡是設定視窗大小,原始版本中沒有考慮實際視訊解析度不是這麼大的問題
// 所以原始程式碼播放其他大小的視訊時出錯
#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);
}
strcpy(is->filename, argv[1]);
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 = "FLUSH";
for(;;)
{
double incr, pos;
SDL_WaitEvent(&event);
switch(event.type)
{
case SDL_KEYDOWN:
switch(event.key.keysym.sym)
{
case SDLK_LEFT:
incr = -1.0;
goto do_seek;
case SDLK_RIGHT:
incr = 1.0;
goto do_seek;
case SDLK_UP:
incr = 6.0;
goto do_seek;
case SDLK_DOWN:
incr = -6.0;
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;
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;
}