avplay.c

/*
 * avplay : Simple Media Player based on the Libav libraries
 * Copyright (c) 2003 Fabrice Bellard
 *
 * This file is part of Libav.
 *
 * Libav is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * Libav is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "config.h"
#include <inttypes.h>
#include <math.h>
#include <limits.h>
#include "libavutil/avstring.h"
#include "libavutil/colorspace.h"
#include "libavutil/mathematics.h"
#include "libavutil/pixdesc.h"
#include "libavutil/imgutils.h"
#include "libavutil/dict.h"
#include "libavutil/parseutils.h"
#include "libavutil/samplefmt.h"
#include "libavformat/avformat.h"
#include "libavdevice/avdevice.h"
#include "libswscale/swscale.h"
#include "libavresample/avresample.h"
#include "libavutil/opt.h"
#include "libavcodec/avfft.h"

#if CONFIG_AVFILTER
# include "libavfilter/avfilter.h"
# include "libavfilter/avfiltergraph.h"
# include "libavfilter/buffersink.h"
# include "libavfilter/buffersrc.h"
#endif

#include "cmdutils.h"

#include <SDL.h>
#include <SDL_thread.h>

#ifdef __MINGW32__
#undef main /* We don't want SDL to override our main() */
#endif

#include <unistd.h>
#include <assert.h>

const char program_name[] = "avplay";
const int program_birth_year = 2003;

#define MAX_QUEUE_SIZE (15 * 1024 * 1024)
#define MIN_AUDIOQ_SIZE (20 * 16 * 1024)
#define MIN_FRAMES 5

/* SDL audio buffer size, in samples. Should be small to have precise
   A/V sync as SDL does not have hardware buffer fullness info. */
#define SDL_AUDIO_BUFFER_SIZE 1024

/* no AV sync correction is done if below the AV sync threshold */
#define AV_SYNC_THRESHOLD 0.01
/* no AV correction is done if too big error */
#define AV_NOSYNC_THRESHOLD 10.0

#define FRAME_SKIP_FACTOR 0.05

/* maximum audio speed change to get correct sync */
#define SAMPLE_CORRECTION_PERCENT_MAX 10

/* we use about AUDIO_DIFF_AVG_NB A-V differences to make the average */
#define AUDIO_DIFF_AVG_NB   20

/* NOTE: the size must be big enough to compensate the hardware audio buffersize size */
#define SAMPLE_ARRAY_SIZE (2 * 65536)

static int sws_flags = SWS_BICUBIC;

typedef struct PacketQueue {
    AVPacketList *first_pkt, *last_pkt;
    int nb_packets;
    int size;
    int abort_request;
    SDL_mutex *mutex;
    SDL_cond *cond;
} PacketQueue;

#define VIDEO_PICTURE_QUEUE_SIZE 2
#define SUBPICTURE_QUEUE_SIZE 4

typedef struct VideoPicture {
    double pts;                                  ///< presentation time stamp for this picture
    double target_clock;                         ///< av_gettime() time at which this should be displayed ideally
    int64_t pos;                                 ///< byte position in file
    SDL_Overlay *bmp;
    int width, height; /* source height & width */
    int allocated;
    int reallocate;
    enum PixelFormat pix_fmt;

#if CONFIG_AVFILTER
    AVFilterBufferRef *picref;
#endif
} VideoPicture;

typedef struct SubPicture {
    double pts; /* presentation time stamp for this picture */
    AVSubtitle sub;
} SubPicture;

enum {
    AV_SYNC_AUDIO_MASTER, /* default choice */
    AV_SYNC_VIDEO_MASTER,
    AV_SYNC_EXTERNAL_CLOCK, /* synchronize to an external clock */
};

typedef struct VideoState {
    SDL_Thread *parse_tid;
    SDL_Thread *video_tid;
    SDL_Thread *refresh_tid;
    AVInputFormat *iformat;
    int no_background;
    int abort_request;
    int paused;
    int last_paused;
    int seek_req;
    int seek_flags;
    int64_t seek_pos;
    int64_t seek_rel;
    int read_pause_return;
    AVFormatContext *ic;

    int audio_stream;

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

    double audio_clock;
    double audio_diff_cum; /* used for AV difference average computation */
    double audio_diff_avg_coef;
    double audio_diff_threshold;
    int audio_diff_avg_count;
    AVStream *audio_st;
    PacketQueue audioq;
    int audio_hw_buf_size;
    uint8_t silence_buf[SDL_AUDIO_BUFFER_SIZE];
    uint8_t *audio_buf;
    uint8_t *audio_buf1;
    unsigned int audio_buf_size; /* in bytes */
    int audio_buf_index; /* in bytes */
    AVPacket audio_pkt_temp;
    AVPacket audio_pkt;
    enum AVSampleFormat sdl_sample_fmt;
    uint64_t sdl_channel_layout;
    int sdl_channels;
    enum AVSampleFormat resample_sample_fmt;
    uint64_t resample_channel_layout;
    AVAudioResampleContext *avr;
    AVFrame *frame;

    int show_audio; /* if true, display audio samples */
    int16_t sample_array[SAMPLE_ARRAY_SIZE];
    int sample_array_index;
    int last_i_start;
    RDFTContext *rdft;
    int rdft_bits;
    FFTSample *rdft_data;
    int xpos;

    SDL_Thread *subtitle_tid;
    int subtitle_stream;
    int subtitle_stream_changed;
    AVStream *subtitle_st;
    PacketQueue subtitleq;
    SubPicture subpq[SUBPICTURE_QUEUE_SIZE];
    int subpq_size, subpq_rindex, subpq_windex;
    SDL_mutex *subpq_mutex;
    SDL_cond *subpq_cond;

    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
    int video_stream;
    AVStream *video_st;
    PacketQueue videoq;
    double video_current_pts;                    ///< current displayed pts (different from video_clock if frame fifos are used)
    double video_current_pts_drift;              ///< video_current_pts - time (av_gettime) at which we updated video_current_pts - used to have running video pts
    int64_t video_current_pos;                   ///< current displayed file pos
    VideoPicture pictq[VIDEO_PICTURE_QUEUE_SIZE];
    int pictq_size, pictq_rindex, pictq_windex;
    SDL_mutex *pictq_mutex;
    SDL_cond *pictq_cond;
#if !CONFIG_AVFILTER
    struct SwsContext *img_convert_ctx;
#endif

    //    QETimer *video_timer;
    char filename[1024];
    int width, height, xleft, ytop;

    PtsCorrectionContext pts_ctx;

#if CONFIG_AVFILTER
    AVFilterContext *in_video_filter;           ///< the first filter in the video chain
    AVFilterContext *out_video_filter;          ///< the last filter in the video chain
    int use_dr1;
    FrameBuffer *buffer_pool;
#endif

    float skip_frames;
    float skip_frames_index;
    int refresh;
} VideoState;

static void show_help(void);

/* options specified by the user */
static AVInputFormat *file_iformat;
static const char *input_filename;
static const char *window_title;
static int fs_screen_width;
static int fs_screen_height;
static int screen_width  = 0;
static int screen_height = 0;
static int audio_disable;
static int video_disable;
static int wanted_stream[AVMEDIA_TYPE_NB] = {
    [AVMEDIA_TYPE_AUDIO]    = -1,
    [AVMEDIA_TYPE_VIDEO]    = -1,
    [AVMEDIA_TYPE_SUBTITLE] = -1,
};
static int seek_by_bytes = -1;
static int display_disable;
static int show_status = 1;
static int av_sync_type = AV_SYNC_AUDIO_MASTER;
static int64_t start_time = AV_NOPTS_VALUE;
static int64_t duration = AV_NOPTS_VALUE;
static int debug = 0;
static int debug_mv = 0;
static int step = 0;
static int workaround_bugs = 1;
static int fast = 0;
static int genpts = 0;
static int idct = FF_IDCT_AUTO;
static enum AVDiscard skip_frame       = AVDISCARD_DEFAULT;
static enum AVDiscard skip_idct        = AVDISCARD_DEFAULT;
static enum AVDiscard skip_loop_filter = AVDISCARD_DEFAULT;
static int error_concealment = 3;
static int decoder_reorder_pts = -1;
static int autoexit;
static int exit_on_keydown;
static int exit_on_mousedown;
static int loop = 1;
static int framedrop = 1;

static int rdftspeed = 20;
#if CONFIG_AVFILTER
static char *vfilters = NULL;
#endif

/* current context */
static int is_full_screen;
static VideoState *cur_stream;
static int64_t audio_callback_time;

static AVPacket flush_pkt;

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

static SDL_Surface *screen;

void exit_program(int ret)
{
    exit(ret);
}

static int packet_queue_put(PacketQueue *q, AVPacket *pkt);

/* packet queue handling */
static void packet_queue_init(PacketQueue *q)
{
    memset(q, 0, sizeof(PacketQueue));
    q->mutex = SDL_CreateMutex();
    q->cond = SDL_CreateCond();
    packet_queue_put(q, &flush_pkt);
}

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);
}

static void packet_queue_end(PacketQueue *q)
{
    packet_queue_flush(q);
    SDL_DestroyMutex(q->mutex);
    SDL_DestroyCond(q->cond);
}

static int packet_queue_put(PacketQueue *q, AVPacket *pkt)
{
    AVPacketList *pkt1;

    /* duplicate the packet */
    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 + sizeof(*pkt1);
    /* XXX: should duplicate packet data in DV case */
    SDL_CondSignal(q->cond);

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

static void packet_queue_abort(PacketQueue *q)
{
    SDL_LockMutex(q->mutex);

    q->abort_request = 1;

    SDL_CondSignal(q->cond);

    SDL_UnlockMutex(q->mutex);
}

/* return < 0 if aborted, 0 if no packet and > 0 if packet.  */
static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block)
{
    AVPacketList *pkt1;
    int ret;

    SDL_LockMutex(q->mutex);

    for (;;) {
        if (q->abort_request) {
            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 + sizeof(*pkt1);
            *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 inline void fill_rectangle(SDL_Surface *screen,
                                  int x, int y, int w, int h, int color)
{
    SDL_Rect rect;
    rect.x = x;
    rect.y = y;
    rect.w = w;
    rect.h = h;
    SDL_FillRect(screen, &rect, color);
}

#define ALPHA_BLEND(a, oldp, newp, s)\
((((oldp << s) * (255 - (a))) + (newp * (a))) / (255 << s))

#define RGBA_IN(r, g, b, a, s)\
{\
    unsigned int v = ((const uint32_t *)(s))[0];\
    a = (v >> 24) & 0xff;\
    r = (v >> 16) & 0xff;\
    g = (v >> 8) & 0xff;\
    b = v & 0xff;\
}

#define YUVA_IN(y, u, v, a, s, pal)\
{\
    unsigned int val = ((const uint32_t *)(pal))[*(const uint8_t*)(s)];\
    a = (val >> 24) & 0xff;\
    y = (val >> 16) & 0xff;\
    u = (val >> 8) & 0xff;\
    v = val & 0xff;\
}

#define YUVA_OUT(d, y, u, v, a)\
{\
    ((uint32_t *)(d))[0] = (a << 24) | (y << 16) | (u << 8) | v;\
}


#define BPP 1

static void blend_subrect(AVPicture *dst, const AVSubtitleRect *rect, int imgw, int imgh)
{
    int wrap, wrap3, width2, skip2;
    int y, u, v, a, u1, v1, a1, w, h;
    uint8_t *lum, *cb, *cr;
    const uint8_t *p;
    const uint32_t *pal;
    int dstx, dsty, dstw, dsth;

    dstw = av_clip(rect->w, 0, imgw);
    dsth = av_clip(rect->h, 0, imgh);
    dstx = av_clip(rect->x, 0, imgw - dstw);
    dsty = av_clip(rect->y, 0, imgh - dsth);
    lum = dst->data[0] + dsty * dst->linesize[0];
    cb  = dst->data[1] + (dsty >> 1) * dst->linesize[1];
    cr  = dst->data[2] + (dsty >> 1) * dst->linesize[2];

    width2 = ((dstw + 1) >> 1) + (dstx & ~dstw & 1);
    skip2 = dstx >> 1;
    wrap = dst->linesize[0];
    wrap3 = rect->pict.linesize[0];
    p = rect->pict.data[0];
    pal = (const uint32_t *)rect->pict.data[1];  /* Now in YCrCb! */

    if (dsty & 1) {
        lum += dstx;
        cb += skip2;
        cr += skip2;

        if (dstx & 1) {
            YUVA_IN(y, u, v, a, p, pal);
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);
            cb[0] = ALPHA_BLEND(a >> 2, cb[0], u, 0);
            cr[0] = ALPHA_BLEND(a >> 2, cr[0], v, 0);
            cb++;
            cr++;
            lum++;
            p += BPP;
        }
        for (w = dstw - (dstx & 1); w >= 2; w -= 2) {
            YUVA_IN(y, u, v, a, p, pal);
            u1 = u;
            v1 = v;
            a1 = a;
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);

            YUVA_IN(y, u, v, a, p + BPP, pal);
            u1 += u;
            v1 += v;
            a1 += a;
            lum[1] = ALPHA_BLEND(a, lum[1], y, 0);
            cb[0] = ALPHA_BLEND(a1 >> 2, cb[0], u1, 1);
            cr[0] = ALPHA_BLEND(a1 >> 2, cr[0], v1, 1);
            cb++;
            cr++;
            p += 2 * BPP;
            lum += 2;
        }
        if (w) {
            YUVA_IN(y, u, v, a, p, pal);
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);
            cb[0] = ALPHA_BLEND(a >> 2, cb[0], u, 0);
            cr[0] = ALPHA_BLEND(a >> 2, cr[0], v, 0);
            p++;
            lum++;
        }
        p += wrap3 - dstw * BPP;
        lum += wrap - dstw - dstx;
        cb += dst->linesize[1] - width2 - skip2;
        cr += dst->linesize[2] - width2 - skip2;
    }
    for (h = dsth - (dsty & 1); h >= 2; h -= 2) {
        lum += dstx;
        cb += skip2;
        cr += skip2;

        if (dstx & 1) {
            YUVA_IN(y, u, v, a, p, pal);
            u1 = u;
            v1 = v;
            a1 = a;
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);
            p += wrap3;
            lum += wrap;
            YUVA_IN(y, u, v, a, p, pal);
            u1 += u;
            v1 += v;
            a1 += a;
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);
            cb[0] = ALPHA_BLEND(a1 >> 2, cb[0], u1, 1);
            cr[0] = ALPHA_BLEND(a1 >> 2, cr[0], v1, 1);
            cb++;
            cr++;
            p += -wrap3 + BPP;
            lum += -wrap + 1;
        }
        for (w = dstw - (dstx & 1); w >= 2; w -= 2) {
            YUVA_IN(y, u, v, a, p, pal);
            u1 = u;
            v1 = v;
            a1 = a;
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);

            YUVA_IN(y, u, v, a, p + BPP, pal);
            u1 += u;
            v1 += v;
            a1 += a;
            lum[1] = ALPHA_BLEND(a, lum[1], y, 0);
            p += wrap3;
            lum += wrap;

            YUVA_IN(y, u, v, a, p, pal);
            u1 += u;
            v1 += v;
            a1 += a;
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);

            YUVA_IN(y, u, v, a, p + BPP, pal);
            u1 += u;
            v1 += v;
            a1 += a;
            lum[1] = ALPHA_BLEND(a, lum[1], y, 0);

            cb[0] = ALPHA_BLEND(a1 >> 2, cb[0], u1, 2);
            cr[0] = ALPHA_BLEND(a1 >> 2, cr[0], v1, 2);

            cb++;
            cr++;
            p += -wrap3 + 2 * BPP;
            lum += -wrap + 2;
        }
        if (w) {
            YUVA_IN(y, u, v, a, p, pal);
            u1 = u;
            v1 = v;
            a1 = a;
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);
            p += wrap3;
            lum += wrap;
            YUVA_IN(y, u, v, a, p, pal);
            u1 += u;
            v1 += v;
            a1 += a;
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);
            cb[0] = ALPHA_BLEND(a1 >> 2, cb[0], u1, 1);
            cr[0] = ALPHA_BLEND(a1 >> 2, cr[0], v1, 1);
            cb++;
            cr++;
            p += -wrap3 + BPP;
            lum += -wrap + 1;
        }
        p += wrap3 + (wrap3 - dstw * BPP);
        lum += wrap + (wrap - dstw - dstx);
        cb += dst->linesize[1] - width2 - skip2;
        cr += dst->linesize[2] - width2 - skip2;
    }
    /* handle odd height */
    if (h) {
        lum += dstx;
        cb += skip2;
        cr += skip2;

        if (dstx & 1) {
            YUVA_IN(y, u, v, a, p, pal);
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);
            cb[0] = ALPHA_BLEND(a >> 2, cb[0], u, 0);
            cr[0] = ALPHA_BLEND(a >> 2, cr[0], v, 0);
            cb++;
            cr++;
            lum++;
            p += BPP;
        }
        for (w = dstw - (dstx & 1); w >= 2; w -= 2) {
            YUVA_IN(y, u, v, a, p, pal);
            u1 = u;
            v1 = v;
            a1 = a;
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);

            YUVA_IN(y, u, v, a, p + BPP, pal);
            u1 += u;
            v1 += v;
            a1 += a;
            lum[1] = ALPHA_BLEND(a, lum[1], y, 0);
            cb[0] = ALPHA_BLEND(a1 >> 2, cb[0], u, 1);
            cr[0] = ALPHA_BLEND(a1 >> 2, cr[0], v, 1);
            cb++;
            cr++;
            p += 2 * BPP;
            lum += 2;
        }
        if (w) {
            YUVA_IN(y, u, v, a, p, pal);
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);
            cb[0] = ALPHA_BLEND(a >> 2, cb[0], u, 0);
            cr[0] = ALPHA_BLEND(a >> 2, cr[0], v, 0);
        }
    }
}

static void free_subpicture(SubPicture *sp)
{
    avsubtitle_free(&sp->sub);
}

static void video_image_display(VideoState *is)
{
    VideoPicture *vp;
    SubPicture *sp;
    AVPicture pict;
    float aspect_ratio;
    int width, height, x, y;
    SDL_Rect rect;
    int i;

    vp = &is->pictq[is->pictq_rindex];
    if (vp->bmp) {
#if CONFIG_AVFILTER
         if (vp->picref->video->pixel_aspect.num == 0)
             aspect_ratio = 0;
         else
             aspect_ratio = av_q2d(vp->picref->video->pixel_aspect);
#else

        /* XXX: use variable in the frame */
        if (is->video_st->sample_aspect_ratio.num)
            aspect_ratio = av_q2d(is->video_st->sample_aspect_ratio);
        else if (is->video_st->codec->sample_aspect_ratio.num)
            aspect_ratio = av_q2d(is->video_st->codec->sample_aspect_ratio);
        else
            aspect_ratio = 0;
#endif
        if (aspect_ratio <= 0.0)
            aspect_ratio = 1.0;
        aspect_ratio *= (float)vp->width / (float)vp->height;

        if (is->subtitle_st)
        {
            if (is->subpq_size > 0)
            {
                sp = &is->subpq[is->subpq_rindex];

                if (vp->pts >= sp->pts + ((float) sp->sub.start_display_time / 1000))
                {
                    SDL_LockYUVOverlay (vp->bmp);

                    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];

                    for (i = 0; i < sp->sub.num_rects; i++)
                        blend_subrect(&pict, sp->sub.rects[i],
                                      vp->bmp->w, vp->bmp->h);

                    SDL_UnlockYUVOverlay (vp->bmp);
                }
            }
        }


        /* XXX: we suppose the screen has a 1.0 pixel ratio */
        height = is->height;
        width = ((int)rint(height * aspect_ratio)) & ~1;
        if (width > is->width) {
            width = is->width;
            height = ((int)rint(width / aspect_ratio)) & ~1;
        }
        x = (is->width - width) / 2;
        y = (is->height - height) / 2;
        is->no_background = 0;
        rect.x = is->xleft + x;
        rect.y = is->ytop  + y;
        rect.w = width;
        rect.h = height;
        SDL_DisplayYUVOverlay(vp->bmp, &rect);
    }
}

/* get the current audio output buffer size, in samples. With SDL, we
   cannot have a precise information */
static int audio_write_get_buf_size(VideoState *is)
{
    return is->audio_buf_size - is->audio_buf_index;
}

static inline int compute_mod(int a, int b)
{
    a = a % b;
    if (a >= 0)
        return a;
    else
        return a + b;
}

static void video_audio_display(VideoState *s)
{
    int i, i_start, x, y1, y, ys, delay, n, nb_display_channels;
    int ch, channels, h, h2, bgcolor, fgcolor;
    int16_t time_diff;
    int rdft_bits, nb_freq;

    for (rdft_bits = 1; (1 << rdft_bits) < 2 * s->height; rdft_bits++)
        ;
    nb_freq = 1 << (rdft_bits - 1);

    /* compute display index : center on currently output samples */
    channels = s->sdl_channels;
    nb_display_channels = channels;
    if (!s->paused) {
        int data_used = s->show_audio == 1 ? s->width : (2 * nb_freq);
        n = 2 * channels;
        delay = audio_write_get_buf_size(s);
        delay /= n;

        /* to be more precise, we take into account the time spent since
           the last buffer computation */
        if (audio_callback_time) {
            time_diff = av_gettime() - audio_callback_time;
            delay -= (time_diff * s->audio_st->codec->sample_rate) / 1000000;
        }

        delay += 2 * data_used;
        if (delay < data_used)
            delay = data_used;

        i_start= x = compute_mod(s->sample_array_index - delay * channels, SAMPLE_ARRAY_SIZE);
        if (s->show_audio == 1) {
            h = INT_MIN;
            for (i = 0; i < 1000; i += channels) {
                int idx = (SAMPLE_ARRAY_SIZE + x - i) % SAMPLE_ARRAY_SIZE;
                int a = s->sample_array[idx];
                int b = s->sample_array[(idx + 4 * channels) % SAMPLE_ARRAY_SIZE];
                int c = s->sample_array[(idx + 5 * channels) % SAMPLE_ARRAY_SIZE];
                int d = s->sample_array[(idx + 9 * channels) % SAMPLE_ARRAY_SIZE];
                int score = a - d;
                if (h < score && (b ^ c) < 0) {
                    h = score;
                    i_start = idx;
                }
            }
        }

        s->last_i_start = i_start;
    } else {
        i_start = s->last_i_start;
    }

    bgcolor = SDL_MapRGB(screen->format, 0x00, 0x00, 0x00);
    if (s->show_audio == 1) {
        fill_rectangle(screen,
                       s->xleft, s->ytop, s->width, s->height,
                       bgcolor);

        fgcolor = SDL_MapRGB(screen->format, 0xff, 0xff, 0xff);

        /* total height for one channel */
        h = s->height / nb_display_channels;
        /* graph height / 2 */
        h2 = (h * 9) / 20;
        for (ch = 0; ch < nb_display_channels; ch++) {
            i = i_start + ch;
            y1 = s->ytop + ch * h + (h / 2); /* position of center line */
            for (x = 0; x < s->width; x++) {
                y = (s->sample_array[i] * h2) >> 15;
                if (y < 0) {
                    y = -y;
                    ys = y1 - y;
                } else {
                    ys = y1;
                }
                fill_rectangle(screen,
                               s->xleft + x, ys, 1, y,
                               fgcolor);
                i += channels;
                if (i >= SAMPLE_ARRAY_SIZE)
                    i -= SAMPLE_ARRAY_SIZE;
            }
        }

        fgcolor = SDL_MapRGB(screen->format, 0x00, 0x00, 0xff);

        for (ch = 1; ch < nb_display_channels; ch++) {
            y = s->ytop + ch * h;
            fill_rectangle(screen,
                           s->xleft, y, s->width, 1,
                           fgcolor);
        }
        SDL_UpdateRect(screen, s->xleft, s->ytop, s->width, s->height);
    } else {
        nb_display_channels= FFMIN(nb_display_channels, 2);
        if (rdft_bits != s->rdft_bits) {
            av_rdft_end(s->rdft);
            av_free(s->rdft_data);
            s->rdft = av_rdft_init(rdft_bits, DFT_R2C);
            s->rdft_bits = rdft_bits;
            s->rdft_data = av_malloc(4 * nb_freq * sizeof(*s->rdft_data));
        }
        {
            FFTSample *data[2];
            for (ch = 0; ch < nb_display_channels; ch++) {
                data[ch] = s->rdft_data + 2 * nb_freq * ch;
                i = i_start + ch;
                for (x = 0; x < 2 * nb_freq; x++) {
                    double w = (x-nb_freq) * (1.0 / nb_freq);
                    data[ch][x] = s->sample_array[i] * (1.0 - w * w);
                    i += channels;
                    if (i >= SAMPLE_ARRAY_SIZE)
                        i -= SAMPLE_ARRAY_SIZE;
                }
                av_rdft_calc(s->rdft, data[ch]);
            }
            // least efficient way to do this, we should of course directly access it but its more than fast enough
            for (y = 0; y < s->height; y++) {
                double w = 1 / sqrt(nb_freq);
                int a = sqrt(w * sqrt(data[0][2 * y + 0] * data[0][2 * y + 0] + data[0][2 * y + 1] * data[0][2 * y + 1]));
                int b = (nb_display_channels == 2 ) ? sqrt(w * sqrt(data[1][2 * y + 0] * data[1][2 * y + 0]
                       + data[1][2 * y + 1] * data[1][2 * y + 1])) : a;
                a = FFMIN(a, 255);
                b = FFMIN(b, 255);
                fgcolor = SDL_MapRGB(screen->format, a, b, (a + b) / 2);

                fill_rectangle(screen,
                            s->xpos, s->height-y, 1, 1,
                            fgcolor);
            }
        }
        SDL_UpdateRect(screen, s->xpos, s->ytop, 1, s->height);
        s->xpos++;
        if (s->xpos >= s->width)
            s->xpos= s->xleft;
    }
}

static int video_open(VideoState *is)
{
    int flags = SDL_HWSURFACE | SDL_ASYNCBLIT | SDL_HWACCEL;
    int w,h;

    if (is_full_screen) flags |= SDL_FULLSCREEN;
    else                flags |= SDL_RESIZABLE;

    if (is_full_screen && fs_screen_width) {
        w = fs_screen_width;
        h = fs_screen_height;
    } else if (!is_full_screen && screen_width) {
        w = screen_width;
        h = screen_height;
#if CONFIG_AVFILTER
    } else if (is->out_video_filter && is->out_video_filter->inputs[0]) {
        w = is->out_video_filter->inputs[0]->w;
        h = is->out_video_filter->inputs[0]->h;
#else
    } else if (is->video_st && is->video_st->codec->width) {
        w = is->video_st->codec->width;
        h = is->video_st->codec->height;
#endif
    } else {
        w = 640;
        h = 480;
    }
    if (screen && is->width == screen->w && screen->w == w
       && is->height== screen->h && screen->h == h)
        return 0;

#if defined(__APPLE__) && !SDL_VERSION_ATLEAST(1, 2, 14)
    /* setting bits_per_pixel = 0 or 32 causes blank video on OS X and older SDL */
    screen = SDL_SetVideoMode(w, h, 24, flags);
#else
    screen = SDL_SetVideoMode(w, h, 0, flags);
#endif
    if (!screen) {
        fprintf(stderr, "SDL: could not set video mode - exiting\n");
        return -1;
    }
    if (!window_title)
        window_title = input_filename;
    SDL_WM_SetCaption(window_title, window_title);

    is->width  = screen->w;
    is->height = screen->h;

    return 0;
}

/* display the current picture, if any */
static void video_display(VideoState *is)
{
    if (!screen)
        video_open(cur_stream);
    if (is->audio_st && is->show_audio)
        video_audio_display(is);
    else if (is->video_st)
        video_image_display(is);
}

static int refresh_thread(void *opaque)
{
    VideoState *is= opaque;
    while (!is->abort_request) {
        SDL_Event event;
        event.type = FF_REFRESH_EVENT;
        event.user.data1 = opaque;
        if (!is->refresh) {
            is->refresh = 1;
            SDL_PushEvent(&event);
        }
        usleep(is->audio_st && is->show_audio ? rdftspeed * 1000 : 5000); // FIXME ideally we should wait the correct time but SDLs event passing is so slow it would be silly
    }
    return 0;
}

/* get the current audio clock value */
static double get_audio_clock(VideoState *is)
{
    double pts;
    int hw_buf_size, bytes_per_sec;
    pts = is->audio_clock;
    hw_buf_size = audio_write_get_buf_size(is);
    bytes_per_sec = 0;
    if (is->audio_st) {
        bytes_per_sec = is->audio_st->codec->sample_rate * is->sdl_channels *
                        av_get_bytes_per_sample(is->sdl_sample_fmt);
    }
    if (bytes_per_sec)
        pts -= (double)hw_buf_size / bytes_per_sec;
    return pts;
}

/* get the current video clock value */
static double get_video_clock(VideoState *is)
{
    if (is->paused) {
        return is->video_current_pts;
    } else {
        return is->video_current_pts_drift + av_gettime() / 1000000.0;
    }
}

/* get the current external clock value */
static double get_external_clock(VideoState *is)
{
    int64_t ti;
    ti = av_gettime();
    return is->external_clock + ((ti - is->external_clock_time) * 1e-6);
}

/* get the current master clock value */
static double get_master_clock(VideoState *is)
{
    double val;

    if (is->av_sync_type == AV_SYNC_VIDEO_MASTER) {