ffplay.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

    }

    /* if the frame is not skipped, then display it */
    if (vp->bmp) {
        /* get a pointer on the bitmap */
        SDL_LockYUVOverlay (vp->bmp);

        dst_pix_fmt = PIX_FMT_YUV420P;
        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];
        img_convert_ctx = sws_getCachedContext(img_convert_ctx,
            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,
            dst_pix_fmt, sws_flags, NULL, NULL, NULL);
        if (img_convert_ctx == NULL) {
            fprintf(stderr, "Cannot initialize the conversion context\n");
            exit(1);
        }
        sws_scale(img_convert_ctx, src_frame->data, src_frame->linesize,
                  0, is->video_st->codec->height, pict.data, pict.linesize);
        /* update the bitmap content */
        SDL_UnlockYUVOverlay(vp->bmp);

        vp->pts = pts;

        /* now we can update the picture count */
        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;
}

/**
 * compute the exact PTS for the picture if it is omitted in the stream
 * @param pts1 the dts of the pkt / pts of the frame
 */
static int output_picture2(VideoState *is, AVFrame *src_frame, double pts1)
{
    double frame_delay, pts;

    pts = pts1;

    if (pts != 0) {
        /* update video clock with pts, if present */
        is->video_clock = pts;
    } else {
        pts = is->video_clock;
    }
    /* update video clock for next frame */
    frame_delay = av_q2d(is->video_st->codec->time_base);
    /* for MPEG2, the frame can be repeated, so we update the
       clock accordingly */
    frame_delay += src_frame->repeat_pict * (frame_delay * 0.5);
    is->video_clock += frame_delay;

#if defined(DEBUG_SYNC) && 0
    {
        int ftype;
        if (src_frame->pict_type == FF_B_TYPE)
            ftype = 'B';
        else if (src_frame->pict_type == FF_I_TYPE)
            ftype = 'I';
        else
            ftype = 'P';
        printf("frame_type=%c clock=%0.3f pts=%0.3f\n",
               ftype, pts, pts1);
    }
#endif
    return queue_picture(is, src_frame, pts);
}

static uint64_t global_video_pkt_pts= AV_NOPTS_VALUE;

static int my_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;
}

static void my_release_buffer(struct AVCodecContext *c, AVFrame *pic){
    if(pic) av_freep(&pic->opaque);
    avcodec_default_release_buffer(c, pic);
}

static int video_thread(void *arg)
{
    VideoState *is = arg;
    AVPacket pkt1, *pkt = &pkt1;
    int len1, got_picture;
    AVFrame *frame= avcodec_alloc_frame();
    double pts;

    for(;;) {
        while (is->paused && !is->videoq.abort_request) {
            SDL_Delay(10);
        }
        if (packet_queue_get(&is->videoq, pkt, 1) < 0)
            break;

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

        /* NOTE: ipts is the PTS of the _first_ picture beginning in
           this packet, if any */
        global_video_pkt_pts= pkt->pts;
        len1 = avcodec_decode_video(is->video_st->codec,
                                    frame, &got_picture,
                                    pkt->data, pkt->size);

        if(   (decoder_reorder_pts || pkt->dts == AV_NOPTS_VALUE)
           && frame->opaque && *(uint64_t*)frame->opaque != AV_NOPTS_VALUE)
            pts= *(uint64_t*)frame->opaque;
        else if(pkt->dts != AV_NOPTS_VALUE)
            pts= pkt->dts;
        else
            pts= 0;
        pts *= av_q2d(is->video_st->time_base);

//            if (len1 < 0)
//                break;
        if (got_picture) {
            if (output_picture2(is, frame, pts) < 0)
                goto the_end;
        }
        av_free_packet(pkt);
        if (step)
            if (cur_stream)
                stream_pause(cur_stream);
    }
 the_end:
    av_free(frame);
    return 0;
}

static int subtitle_thread(void *arg)
{
    VideoState *is = arg;
    SubPicture *sp;
    AVPacket pkt1, *pkt = &pkt1;
    int len1, got_subtitle;
    double pts;
    int i, j;
    int r, g, b, y, u, v, a;

    for(;;) {
        while (is->paused && !is->subtitleq.abort_request) {
            SDL_Delay(10);
        }
        if (packet_queue_get(&is->subtitleq, pkt, 1) < 0)
            break;

        if(pkt->data == flush_pkt.data){
            avcodec_flush_buffers(is->subtitle_st->codec);
            continue;
        }
        SDL_LockMutex(is->subpq_mutex);
        while (is->subpq_size >= SUBPICTURE_QUEUE_SIZE &&
               !is->subtitleq.abort_request) {
            SDL_CondWait(is->subpq_cond, is->subpq_mutex);
        }
        SDL_UnlockMutex(is->subpq_mutex);

        if (is->subtitleq.abort_request)
            goto the_end;

        sp = &is->subpq[is->subpq_windex];

       /* NOTE: ipts is the PTS of the _first_ picture beginning in
           this packet, if any */
        pts = 0;
        if (pkt->pts != AV_NOPTS_VALUE)
            pts = av_q2d(is->subtitle_st->time_base)*pkt->pts;

        len1 = avcodec_decode_subtitle(is->subtitle_st->codec,
                                    &sp->sub, &got_subtitle,
                                    pkt->data, pkt->size);
//            if (len1 < 0)
//                break;
        if (got_subtitle && sp->sub.format == 0) {
            sp->pts = pts;

            for (i = 0; i < sp->sub.num_rects; i++)
            {
                for (j = 0; j < sp->sub.rects[i].nb_colors; j++)
                {
                    RGBA_IN(r, g, b, a, sp->sub.rects[i].rgba_palette + j);
                    y = RGB_TO_Y_CCIR(r, g, b);
                    u = RGB_TO_U_CCIR(r, g, b, 0);
                    v = RGB_TO_V_CCIR(r, g, b, 0);
                    YUVA_OUT(sp->sub.rects[i].rgba_palette + j, y, u, v, a);
                }
            }

            /* now we can update the picture count */
            if (++is->subpq_windex == SUBPICTURE_QUEUE_SIZE)
                is->subpq_windex = 0;
            SDL_LockMutex(is->subpq_mutex);
            is->subpq_size++;
            SDL_UnlockMutex(is->subpq_mutex);
        }
        av_free_packet(pkt);
//        if (step)
//            if (cur_stream)
//                stream_pause(cur_stream);
    }
 the_end:
    return 0;
}

/* copy samples for viewing in editor window */
static void update_sample_display(VideoState *is, short *samples, int samples_size)
{
    int size, len, channels;

    channels = is->audio_st->codec->channels;

    size = samples_size / sizeof(short);
    while (size > 0) {
        len = SAMPLE_ARRAY_SIZE - is->sample_array_index;
        if (len > size)
            len = size;
        memcpy(is->sample_array + is->sample_array_index, samples, len * sizeof(short));
        samples += len;
        is->sample_array_index += len;
        if (is->sample_array_index >= SAMPLE_ARRAY_SIZE)
            is->sample_array_index = 0;
        size -= len;
    }
}

/* return the new audio buffer size (samples can be added or deleted
   to get better sync if video or external master clock) */
static int synchronize_audio(VideoState *is, short *samples,
                             int samples_size1, double pts)
{
    int n, samples_size;
    double ref_clock;

    n = 2 * is->audio_st->codec->channels;
    samples_size = samples_size1;

    /* if not master, then we try to remove or add samples to correct the clock */
    if (((is->av_sync_type == AV_SYNC_VIDEO_MASTER && is->video_st) ||
         is->av_sync_type == AV_SYNC_EXTERNAL_CLOCK)) {
        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) {
            is->audio_diff_cum = diff + is->audio_diff_avg_coef * is->audio_diff_cum;
            if (is->audio_diff_avg_count < AUDIO_DIFF_AVG_NB) {
                /* not enough measures to have a correct estimate */
                is->audio_diff_avg_count++;
            } else {
                /* estimate the A-V difference */
                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);
                    nb_samples = samples_size / n;

                    min_size = ((nb_samples * (100 - SAMPLE_CORRECTION_PERCENT_MAX)) / 100) * n;
                    max_size = ((nb_samples * (100 + SAMPLE_CORRECTION_PERCENT_MAX)) / 100) * n;
                    if (wanted_size < min_size)
                        wanted_size = min_size;
                    else if (wanted_size > max_size)
                        wanted_size = max_size;

                    /* add or remove samples to correction the synchro */
                    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 */
                        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;
                    }
                }
#if 0
                printf("diff=%f adiff=%f sample_diff=%d apts=%0.3f vpts=%0.3f %f\n",
                       diff, avg_diff, samples_size - samples_size1,
                       is->audio_clock, is->video_clock, is->audio_diff_threshold);
#endif
            }
        } else {
            /* too big difference : may be initial PTS errors, so
               reset A-V filter */
            is->audio_diff_avg_count = 0;
            is->audio_diff_cum = 0;
        }
    }

    return samples_size;
}

/* decode one audio frame and returns its uncompressed size */
static int audio_decode_frame(VideoState *is, uint8_t *audio_buf, int buf_size, double *pts_ptr)
{
    AVPacket *pkt = &is->audio_pkt;
    int n, len1, data_size;
    double pts;

    for(;;) {
        /* NOTE: the audio packet can contain several frames */
        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, we skip the frame */
                is->audio_pkt_size = 0;
                break;
            }

            is->audio_pkt_data += len1;
            is->audio_pkt_size -= len1;
            if (data_size <= 0)
                continue;
            /* if no pts, then compute it */
            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);
#if defined(DEBUG_SYNC)
            {
                static double last_clock;
                printf("audio: delay=%0.3f clock=%0.3f pts=%0.3f\n",
                       is->audio_clock - last_clock,
                       is->audio_clock, pts);
                last_clock = is->audio_clock;
            }
#endif
            return data_size;
        }

        /* free the current packet */
        if (pkt->data)
            av_free_packet(pkt);

        if (is->paused || is->audioq.abort_request) {
            return -1;
        }

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

/* 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;
}


/* prepare a new audio buffer */
void sdl_audio_callback(void *opaque, Uint8 *stream, int len)
{
    VideoState *is = opaque;
    int audio_size, len1;
    double pts;

    audio_callback_time = av_gettime();

    while (len > 0) {
        if (is->audio_buf_index >= is->audio_buf_size) {
           audio_size = audio_decode_frame(is, is->audio_buf, sizeof(is->audio_buf), &pts);
           if (audio_size < 0) {
                /* if error, just output silence */
               is->audio_buf_size = 1024;
               memset(is->audio_buf, 0, is->audio_buf_size);
           } else {
               if (is->show_audio)
                   update_sample_display(is, (int16_t *)is->audio_buf, audio_size);
               audio_size = synchronize_audio(is, (int16_t *)is->audio_buf, audio_size,