tvi_v4l2.c

自己移植的linux下的流媒体播放器原代码,支持mms协议,支持ftp和http协议.

    /* start audio thread */
    priv->shutdown = 0;
    priv->audio_skew_measure_time = 0;
    priv->first_frame = 0;
    priv->audio_skew = 0;
    priv->first = 1;

    if (priv->input.audioset) {
	set_mute(priv, 0);
    }
    
    return 1;
}


#ifdef HAVE_TV_BSDBT848
static double grabimmediate_video_frame(priv_t *priv, char *buffer, int len)
{
    memset(buffer, 0xCC, len);
    return(1);
}
#endif /* HAVE_TV_BSDBT848 */

// copies a video frame
// for YV12 swaps the 2nd and 3rd plane
static inline void copy_frame(priv_t *priv, unsigned char *dest, unsigned char *source)
{
    int w = priv->format.fmt.pix.width;
    int h = priv->format.fmt.pix.height;
    int d = pixfmt2depth(priv->format.fmt.pix.pixelformat);
    int bytesperline = w*d/8;

    // YV12 uses VIDEO_PALETTE_YUV420P, but the planes are swapped
    switch (priv->mp_format) {
    case IMGFMT_YV12:
	memcpy(dest, source, w * h);
	memcpy(dest+w * h*5/4, source+w * h, w * h/4);
	memcpy(dest+w * h, source+w * h*5/4, w * h/4);
	break;
    default:
	memcpy(dest, source, bytesperline * h);
    }
    
}

// maximum skew change, in frames
#define MAX_SKEW_DELTA 0.6
static void *video_grabber(void *data)
{
    priv_t *priv = (priv_t*)data;
    long long skew, prev_skew, xskew, interval, prev_interval;
    int i;
    int framesize = priv->format.fmt.pix.height*priv->format.fmt.pix.width*
	pixfmt2depth(priv->format.fmt.pix.pixelformat)/8;
    fd_set rdset;
    struct timeval timeout;
    struct v4l2_buffer buf;

    xskew = 0;
    skew = 0;
    interval = 0;
    prev_interval = 0;
    prev_skew = 0;

    mp_msg(MSGT_TV, MSGL_V, "%s: going to capture\n", info.short_name);
    if (ioctl(priv->video_fd, VIDIOC_STREAMON, &(priv->format.type)) < 0) {
	mp_msg(MSGT_TV, MSGL_ERR, "%s: ioctl streamon failed: %s\n",
	       info.short_name, strerror(errno));
	return 0;
    }
    priv->streamon = 1;

    if (!tv_param_noaudio) {
	pthread_mutex_init(&priv->skew_mutex, NULL);
	pthread_create(&priv->audio_grabber_thread, NULL, audio_grabber, priv);
    }

    for (priv->frames = 0; !priv->shutdown;)
    {
	int ret;
	
	if (priv->immediate_mode) {
	    while (priv->video_cnt == priv->video_buffer_size_max) {
		usleep(10000);
		if (priv->shutdown) {
		    return NULL;
		}
	    }
	}
		
	FD_ZERO (&rdset);
	FD_SET (priv->video_fd, &rdset);

	timeout.tv_sec = 1;
	timeout.tv_usec = 0;

	i = select(priv->video_fd + 1, &rdset, NULL, NULL, &timeout);
	if (i < 0) {
	    mp_msg(MSGT_TV, MSGL_ERR, "%s: select failed: %s\n",
		   info.short_name, strerror(errno));
	    continue;
	}
	else if (i == 0) {
	    mp_msg(MSGT_TV, MSGL_ERR, "%s: select timeout\n", info.short_name);
	    continue;
	}
	else if (!FD_ISSET(priv->video_fd, &rdset)) {
	    continue;
	}

	memset(&buf,0,sizeof(buf));
	buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	ret = ioctl(priv->video_fd, VIDIOC_DQBUF, &buf);

	if (ret < 0) {
	    /*
	      if there's no signal, the buffer might me dequeued
	      so we query all the buffers to see which one we should
	      put back to queue

	      observed with saa7134 0.2.8
	      don't know if is it a bug or (mis)feature
	     */
	    mp_msg(MSGT_TV, MSGL_ERR, "%s: ioctl dequeue buffer failed: %s, idx = %d\n",
		   info.short_name, strerror(errno), buf.index);
	    for (i = 0; i < priv->mapcount; i++) {
		memset(&buf,0,sizeof(buf));
		buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
		buf.index = i;
		ret = ioctl(priv->video_fd, VIDIOC_QUERYBUF, &buf);
		if (ret < 0) {
		    mp_msg(MSGT_TV, MSGL_ERR, "%s: ioctl query buffer failed: %s, idx = %d\n",
			   info.short_name, strerror(errno), buf.index);
		    return 0;
		}
		if ((buf.flags & (V4L2_BUF_FLAG_QUEUED | V4L2_BUF_FLAG_MAPPED | V4L2_BUF_FLAG_DONE)) == V4L2_BUF_FLAG_MAPPED) {
		    if (ioctl(priv->video_fd, VIDIOC_QBUF, &(priv->map[i].buf)) < 0) {
			mp_msg(MSGT_TV, MSGL_ERR, "%s: ioctl queue buffer failed: %s\n",
			       info.short_name, strerror(errno));
			return 0;
		    }		
		}
	    }
	    continue;
	}

	/* store the timestamp of the very first frame as reference */
	if (!priv->frames++) {
	    pthread_mutex_lock(&priv->skew_mutex);
	    priv->first_frame = (long long)1e6*buf.timestamp.tv_sec + buf.timestamp.tv_usec;
	    pthread_mutex_unlock(&priv->skew_mutex);
	}
	priv->curr_frame = (long long)buf.timestamp.tv_sec*1e6+buf.timestamp.tv_usec;
//	fprintf(stderr, "idx = %d, ts = %lf\n", buf.index, (double)(priv->curr_frame) / 1e6);

	interval = priv->curr_frame - priv->first_frame;

	if (!priv->immediate_mode) {
	    // interpolate the skew in time
	    pthread_mutex_lock(&priv->skew_mutex);
	    xskew = priv->audio_skew + (interval - priv->audio_skew_measure_time)*priv->audio_skew_factor;
	    pthread_mutex_unlock(&priv->skew_mutex);
 	    // correct extreme skew changes to avoid (especially) moving backwards in time
	    if (xskew - prev_skew > (interval - prev_interval)*MAX_SKEW_DELTA) {
		skew = prev_skew + (interval - prev_interval)*MAX_SKEW_DELTA;
	    } else if (xskew - prev_skew < -(interval - prev_interval)*MAX_SKEW_DELTA) {
		skew = prev_skew - (interval - prev_interval)*MAX_SKEW_DELTA;
	    } else {
		skew = xskew;
	    }
	}

	mp_msg(MSGT_TV, MSGL_DBG3, "\nfps = %lf, interval = %lf, a_skew = %f, corr_skew = %f\n",
	       (interval != prev_interval) ? (double)1e6/(interval - prev_interval) : -1,
	       (double)1e-6*interval, (double)1e-6*xskew, (double)1e-6*skew);
	mp_msg(MSGT_TV, MSGL_DBG3, "vcnt = %d, acnt = %d\n", priv->video_cnt, priv->audio_cnt);

	prev_skew = skew;
	prev_interval = interval;

	/* allocate a new buffer, if needed */
	pthread_mutex_lock(&priv->video_buffer_mutex);
	if (priv->video_buffer_size_current < priv->video_buffer_size_max) {
	    if (priv->video_cnt == priv->video_buffer_size_current) {
		unsigned char *newbuf = (unsigned char*)malloc(framesize);
		if (newbuf) {
		    memmove(priv->video_ringbuffer+priv->video_tail+1, priv->video_ringbuffer+priv->video_tail,
			    (priv->video_buffer_size_current-priv->video_tail)*sizeof(unsigned char *));
		    memmove(priv->video_timebuffer+priv->video_tail+1, priv->video_timebuffer+priv->video_tail,
			    (priv->video_buffer_size_current-priv->video_tail)*sizeof(long long));
		    priv->video_ringbuffer[priv->video_tail] = newbuf;
		    if ((priv->video_head >= priv->video_tail) && (priv->video_cnt > 0)) priv->video_head++;
		    priv->video_buffer_size_current++;
		}
	    }
	}
	pthread_mutex_unlock(&priv->video_buffer_mutex);

	if (priv->video_cnt == priv->video_buffer_size_current) {
	    if (!priv->immediate_mode) {
		mp_msg(MSGT_TV, MSGL_ERR, "\nvideo buffer full - dropping frame\n");
	    }
	} else {
	    if (priv->immediate_mode) {
		priv->video_timebuffer[priv->video_tail] = 0;
	    } else {
		// compensate for audio skew
		// negative skew => there are more audio samples, increase interval
		// positive skew => less samples, shorten the interval
		priv->video_timebuffer[priv->video_tail] = interval - skew;
	    }
		
	    copy_frame(priv, priv->video_ringbuffer[priv->video_tail], priv->map[buf.index].addr);
	    priv->video_tail = (priv->video_tail+1)%priv->video_buffer_size_current;
	    priv->video_cnt++;
	}
	if (ioctl(priv->video_fd, VIDIOC_QBUF, &buf) < 0) {
	    mp_msg(MSGT_TV, MSGL_ERR, "%s: ioctl queue buffer failed: %s\n",
		   info.short_name, strerror(errno));
	    return 0;
	}
    }
    return NULL;
}

static double grab_video_frame(priv_t *priv, char *buffer, int len)
{
    double interval;

    if (priv->first) {
	pthread_create(&priv->video_grabber_thread, NULL, video_grabber, priv);
	priv->first = 0;
    }

    while (priv->video_cnt == 0) {
	usleep(10000);
    }

    pthread_mutex_lock(&priv->video_buffer_mutex);
    interval = (double)priv->video_timebuffer[priv->video_head]*1e-6;
    memcpy(buffer, priv->video_ringbuffer[priv->video_head], len);
    priv->video_cnt--;
    priv->video_head = (priv->video_head+1)%priv->video_buffer_size_current;
    pthread_mutex_unlock(&priv->video_buffer_mutex);

    return interval;
}

static int get_video_framesize(priv_t *priv)
{
    return priv->format.fmt.pix.sizeimage;
}

//#define DOUBLESPEED
#ifdef DOUBLESPEED
// for testing purposes only
static void read_doublespeed(priv_t *priv)
{
    char *bufx = (char*)malloc(priv->audio_in.blocksize*2);
    short *s;
    short *d;
    int i;
    
    audio_in_read_chunk(&priv->audio_in, bufx);
    audio_in_read_chunk(&priv->audio_in, bufx+priv->audio_in.blocksize);

    s = bufx;
    d = priv->audio_ringbuffer+priv->audio_tail*priv->audio_in.blocksize;
    for (i = 0; i < priv->audio_in.blocksize/2; i++) {
	*d++ = *s++;
	*s++;
    }
    
}
#endif

static void *audio_grabber(void *data)
{
    priv_t *priv = (priv_t*)data;
    struct timeval tv;
    int i, audio_skew_ptr = 0;
    long long current_time, prev_skew = 0, prev_skew_uncorr = 0;
    long long start_time_avg;

    gettimeofday(&tv, NULL);
    start_time_avg = priv->audio_start_time = (long long)1e6*tv.tv_sec + tv.tv_usec;
    audio_in_start_capture(&priv->audio_in);
    for (i = 0; i < priv->aud_skew_cnt; i++)
	priv->audio_skew_buffer[i] = 0;
    for (i = 0; i < priv->aud_skew_cnt; i++)
	priv->audio_skew_delta_buffer[i] = 0;

    for (; !priv->shutdown;)
    {
#ifdef DOUBLESPEED
	read_doublespeed(priv);
#else
	if (audio_in_read_chunk(&priv->audio_in, priv->audio_ringbuffer+priv->audio_tail*priv->audio_in.blocksize) < 0)
	    continue;
#endif
	pthread_mutex_lock(&priv->skew_mutex);
	if (priv->first_frame == 0) {
	    // there is no first frame yet (unlikely to happen)
	    gettimeofday(&tv, NULL);
	    start_time_avg = priv->audio_start_time = (long long)1e6*tv.tv_sec + tv.tv_usec;
//	    fprintf(stderr, "warning - first frame not yet available!\n");
	    pthread_mutex_unlock(&priv->skew_mutex);
	    continue;
	}
	pthread_mutex_unlock(&priv->skew_mutex);

	gettimeofday(&tv, NULL);

	priv->audio_recv_blocks_total++;
	current_time = (long long)1e6*tv.tv_sec + tv.tv_usec - priv->audio_start_time;

	if (priv->audio_recv_blocks_total < priv->aud_skew_cnt*2) {
	    start_time_avg += (long long)1e6*tv.tv_sec + tv.tv_usec - 1e6*priv->audio_secs_per_block*priv->audio_recv_blocks_total;
	    priv->audio_start_time = start_time_avg/(priv->audio_recv_blocks_total+1);
	}

//	fprintf(stderr, "spb = %lf, bs = %d, skew = %lf\n", priv->audio_secs_per_block, priv->audio_in.blocksize,
//		(double)(current_time - 1e6*priv->audio_secs_per_block*priv->audio_recv_blocks_total)/1e6);

	// put the current skew into the ring buffer
	priv->audio_skew_total -= priv->audio_skew_buffer[audio_skew_ptr];
	priv->audio_skew_buffer[audio_skew_ptr] = current_time
	    - 1e6*priv->audio_secs_per_block*priv->audio_recv_blocks_total;
	priv->audio_skew_total += priv->audio_skew_buffer[audio_skew_ptr];

	pthread_mutex_lock(&priv->skew_mutex);

	// skew calculation

	// compute the sliding average of the skews
	if (priv->audio_recv_blocks_total > priv->aud_skew_cnt) {
	    priv->audio_skew = priv->audio_skew_total/priv->aud_skew_cnt;
	} else {
	    priv->audio_skew = priv->audio_skew_total/priv->audio_recv_blocks_total;
	}

	// put the current skew change (skew-prev_skew) into the ring buffer
	priv->audio_skew_delta_total -= priv->audio_skew_delta_buffer[audio_skew_ptr];
	priv->audio_skew_delta_buffer[audio_skew_ptr] = priv->audio_skew - prev_skew_uncorr;
	priv->audio_skew_delta_total += priv->audio_skew_delta_buffer[audio_skew_ptr];
	prev_skew_uncorr = priv->audio_skew; // remember the _uncorrected_ average value

	audio_skew_ptr = (audio_skew_ptr+1) % priv->aud_skew_cnt; // rotate the buffer pointer

	// sliding average approximates the value in the middle of the interval
	// so interpolate the skew value further to the current time
	priv->audio_skew += priv->audio_skew_delta_total/2;

	// now finally, priv->audio_skew contains fairly good approximation
	// of the current value 

	// current skew factor (assuming linearity)
	// used for further interpolation in video_grabber
	// probably overkill but seems to be necessary for
	// stress testing by dropping half of the audio frames ;)
	// especially when using ALSA with large block sizes
	// where audio_skew remains a long while behind
	if ((priv->audio_skew_measure_time != 0) && (current_time - priv->audio_skew_measure_time != 0)) {
	    priv->audio_skew_factor = (double)(priv->audio_skew-prev_skew)/(current_time - priv->audio_skew_measure_time);
	} else {
	    priv->audio_skew_factor = 0.0;
	}

	priv->audio_skew_measure_time = current_time;
	prev_skew = priv->audio_skew;
	priv->audio_skew += priv->audio_start_time - priv->first_frame;
	pthread_mutex_unlock(&priv->skew_mutex);
	
//	fprintf(stderr, "audio_skew = %lf, delta = %lf\n", (double)priv->audio_skew/1e6, (double)priv->audio_skew_delta_total/1e6);

	if ((priv->audio_tail+1) % priv->audio_buffer_size == priv->audio_head) {
	    mp_msg(MSGT_TV, MSGL_ERR, "\ntoo bad - dropping audio frame !\n");
	    priv->audio_drop++;
	} else {
	    priv->audio_tail = (priv->audio_tail+1) % priv->audio_buffer_size;
	    priv->audio_cnt++;
	}
    }
    return NULL;
}

static double grab_audio_frame(priv_t *priv, char *buffer, int len)
{
    mp_dbg(MSGT_TV, MSGL_DBG2, "grab_audio_frame(priv=%p, buffer=%p, len=%d)\n",
	priv, buffer, len);

    if (priv->first) {
        pthread_create(&priv->video_grabber_thread, NULL, video_grabber, priv);
        priv->first = 0;
    }

    // compensate for dropped audio frames
    if (priv->audio_drop && (priv->audio_head == priv->audio_tail)) {
	priv->audio_drop--;
	priv->audio_sent_blocks_total++;
	memset(buffer, 0, len);
	return (double)priv->audio_sent_blocks_total*priv->audio_secs_per_block;
    }

    while (priv->audio_head == priv->audio_tail) {
	usleep(10000);
    }
    memcpy(buffer, priv->audio_ringbuffer+priv->audio_head*priv->audio_in.blocksize, len);
    priv->audio_head = (priv->audio_head+1) % priv->audio_buffer_size;
    priv->audio_cnt--;
    priv->audio_sent_blocks_total++;
    return (double)priv->audio_sent_blocks_total*priv->audio_secs_per_block;
}

static int get_audio_framesize(priv_t *priv)
{
    return(priv->audio_in.blocksize);
}

#endif /* USE_TV && HAVE_TV_V4L2 */