ffplay.c

ffmpeg源码分析

    const uint8_t *p;
    const uint32_t *pal;

    lum = dst->data[0] + rect->y * dst->linesize[0];
    cb = dst->data[1] + (rect->y >> 1) * dst->linesize[1];
    cr = dst->data[2] + (rect->y >> 1) * dst->linesize[2];

    width2 = (rect->w + 1) >> 1;
    skip2 = rect->x >> 1;
    wrap = dst->linesize[0];
    wrap3 = rect->linesize;
    p = rect->bitmap;
    pal = rect->rgba_palette;  /* Now in YCrCb! */

    if (rect->y & 1) {
        lum += rect->x;
        cb += skip2;
        cr += skip2;

        if (rect->x & 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 = rect->w - (rect->x & 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 += wrap3 + (wrap3 - rect->w * BPP);
        lum += wrap + (wrap - rect->w - rect->x);
        cb += dst->linesize[1] - width2 - skip2;
        cr += dst->linesize[2] - width2 - skip2;
    }
    for(h = rect->h - (rect->y & 1); h >= 2; h -= 2) {
        lum += rect->x;
        cb += skip2;
        cr += skip2;

        if (rect->x & 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 = rect->w - (rect->x & 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, 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, 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 - rect->w * BPP);
        lum += wrap + (wrap - rect->w - rect->x);
        cb += dst->linesize[1] - width2 - skip2;
        cr += dst->linesize[2] - width2 - skip2;
    }
    /* handle odd height */
    if (h) {
        lum += rect->x;
        cb += skip2;
        cr += skip2;

        if (rect->x & 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 = rect->w - (rect->x & 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)
{
    int i;

    for (i = 0; i < sp->sub.num_rects; i++)
    {
        av_free(sp->sub.rects[i].bitmap);
        av_free(sp->sub.rects[i].rgba_palette);
    }

    av_free(sp->sub.rects);

    memset(&sp->sub, 0, sizeof(AVSubtitle));
}

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) {
        /* XXX: use variable in the frame */
        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;
        /* if an active format is indicated, then it overrides the
           mpeg format */
#if 0
        if (is->video_st->codec->dtg_active_format != is->dtg_active_format) {
            is->dtg_active_format = is->video_st->codec->dtg_active_format;
            printf("dtg_active_format=%d\n", is->dtg_active_format);
        }
#endif
#if 0
        switch(is->video_st->codec->dtg_active_format) {
        case FF_DTG_AFD_SAME:
        default:
            /* nothing to do */
            break;
        case FF_DTG_AFD_4_3:
            aspect_ratio = 4.0 / 3.0;
            break;
        case FF_DTG_AFD_16_9:
            aspect_ratio = 16.0 / 9.0;
            break;
        case FF_DTG_AFD_14_9:
            aspect_ratio = 14.0 / 9.0;
            break;
        case FF_DTG_AFD_4_3_SP_14_9:
            aspect_ratio = 14.0 / 9.0;
            break;
        case FF_DTG_AFD_16_9_SP_14_9:
            aspect_ratio = 14.0 / 9.0;
            break;
        case FF_DTG_AFD_SP_4_3:
            aspect_ratio = 4.0 / 3.0;
            break;
        }
#endif

        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]);

                    SDL_UnlockYUVOverlay (vp->bmp);
                }
            }
        }


        /* XXX: we suppose the screen has a 1.0 pixel ratio */
        height = is->height;
        width = ((int)rint(height * aspect_ratio)) & -3;
        if (width > is->width) {
            width = is->width;
            height = ((int)rint(width / aspect_ratio)) & -3;
        }
        x = (is->width - width) / 2;
        y = (is->height - height) / 2;
        if (!is->no_background) {
            /* fill the background */
            //            fill_border(is, x, y, width, height, QERGB(0x00, 0x00, 0x00));
        } else {
            is->no_background = 0;
        }
        rect.x = is->xleft + x;
        rect.y = is->xleft + y;
        rect.w = width;
        rect.h = height;
        SDL_DisplayYUVOverlay(vp->bmp, &rect);
    } else {
#if 0
        fill_rectangle(screen,
                       is->xleft, is->ytop, is->width, is->height,
                       QERGB(0x00, 0x00, 0x00));
#endif
    }
}

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;

    /* compute display index : center on currently output samples */
    channels = s->audio_st->codec->channels;
    nb_display_channels = channels;
    if (!s->paused) {
        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 -= s->width / 2;
        if (delay < s->width)
            delay = s->width;
        i_start = compute_mod(s->sample_array_index - delay * channels, SAMPLE_ARRAY_SIZE);
        s->last_i_start = i_start;
    } else {
        i_start = s->last_i_start;
    }

    bgcolor = SDL_MapRGB(screen->format, 0x00, 0x00, 0x00);
    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);
}

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

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);
}

/* 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 *
            2 * is->audio_st->codec->channels;
    }
    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)