如何使用speex抖动缓冲区

Question

我正在使用speex库来编码、解码和预处理音频数据。我认为speex库非常有用，但是当我使用speex 抖动缓冲区时，我遇到了一些问题。我使用多线程，一个线程将接收到的数据放入抖动缓冲区，另一个线程从活动抖动缓冲区获取数据，有时“获取”线程无法获得有效的数据，特别是当它比“放置数据”线程更快的时候。此外，我正在使用互斥保护抖动缓冲区。

我不知道如何准确地使用抖动缓冲区。我希望有人能帮我。

这是我的密码：

speex_jitter_buffer.h

#include <speex/speex_jitter.h>
#include <speex/speex.h>

/** @defgroup SpeexJitter SpeexJitter: Adaptive jitter buffer specifically for Speex
 *  This is the jitter buffer that reorders UDP/RTP packets and adjusts the buffer size
 * to maintain good quality and low latency. This is a simplified version that works only
 * with Speex, but is much easier to use.
 *  @{
*/

/** Speex jitter-buffer state. Never use it directly! */
typedef struct SpeexJitter {
   SpeexBits current_packet;         /**< Current Speex packet */
   int valid_bits;                   /**< True if Speex bits are valid */
   JitterBuffer *packets;            /**< Generic jitter buffer state */
   void *dec;                        /**< Pointer to Speex decoder */
   spx_int32_t frame_size;           /**< Frame size of Speex decoder */
} SpeexJitter;

/** Initialise jitter buffer 
 * 
 * @param jitter State of the Speex jitter buffer
 * @param decoder Speex decoder to call
 * @param sampling_rate Sampling rate used by the decoder
*/
void speex_jitter_init(SpeexJitter *jitter, void *decoder, int sampling_rate);

/** Destroy jitter buffer */
void speex_jitter_destroy(SpeexJitter *jitter);

/** Put one packet into the jitter buffer */
void speex_jitter_put(SpeexJitter *jitter, char *packet, int len, int timestamp);

/** Get one packet from the jitter buffer */
void speex_jitter_get(SpeexJitter *jitter, spx_int16_t *out, int *start_offset);

/** Get pointer timestamp of jitter buffer */
int speex_jitter_get_pointer_timestamp(SpeexJitter *jitter);

#ifdef __cplusplus
}
#endif

speex_jitter_buffer.cpp

#include <speex/speex_jitter.h>
#include "speex_jitter_buffer.h"

#ifndef NULL
#define NULL 0
#endif


void speex_jitter_init(SpeexJitter *jitter, void *decoder, int sampling_rate)
{
   jitter->dec = decoder;
   speex_decoder_ctl(decoder, SPEEX_GET_FRAME_SIZE, &jitter->frame_size);

   jitter->packets = jitter_buffer_init(jitter->frame_size);

   speex_bits_init(&jitter->current_packet);
   jitter->valid_bits = 0;

}

void speex_jitter_destroy(SpeexJitter *jitter)
{
   jitter_buffer_destroy(jitter->packets);
   speex_bits_destroy(&jitter->current_packet);
}

void speex_jitter_put(SpeexJitter *jitter, char *packet, int len, int timestamp)
{
   JitterBufferPacket p;
   p.data = packet;
   p.len = len;
   p.timestamp = timestamp;
   p.span = jitter->frame_size;
   jitter_buffer_put(jitter->packets, &p);
}

void speex_jitter_get(SpeexJitter *jitter, spx_int16_t *out, int *current_timestamp)
{
   int i;
   int ret;
   spx_int32_t activity;
   char data[2048];
   JitterBufferPacket packet;
   packet.data = data;

   if (jitter->valid_bits)
   {
      /* Try decoding last received packet */
      ret = speex_decode_int(jitter->dec, &jitter->current_packet, out);
      if (ret == 0)
      {
         jitter_buffer_tick(jitter->packets);
         return;
      } else {
         jitter->valid_bits = 0;
      }
   }

   ret = jitter_buffer_get(jitter->packets, &packet, jitter->frame_size, NULL);

   if (ret != JITTER_BUFFER_OK)
   {
      /* No packet found */

      /*fprintf (stderr, "lost/late frame\n");*/
      /*Packet is late or lost*/
      speex_decode_int(jitter->dec, NULL, out);
   } else {
      speex_bits_read_from(&jitter->current_packet, packet.data, packet.len);
      /* Decode packet */
      ret = speex_decode_int(jitter->dec, &jitter->current_packet, out);
      if (ret == 0)
      {
         jitter->valid_bits = 1;
      } else {
         /* Error while decoding */
         for (i=0;i<jitter->frame_size;i++)
            out[i]=0;
      }
   }
   speex_decoder_ctl(jitter->dec, SPEEX_GET_ACTIVITY, &activity);
   if (activity < 30)
      jitter_buffer_update_delay(jitter->packets, &packet, NULL);
   jitter_buffer_tick(jitter->packets);
}

int speex_jitter_get_pointer_timestamp(SpeexJitter *jitter)
{
   return jitter_buffer_get_pointer_timestamp(jitter->packets);
}

然后我使用"speex_jitter_buffer.h“头文件。

“放置”线程代码：

m_jitter_mutex.lock();
speex_jitter_put(&jitter, recvBuf, payloadLength, timestamp);
m_jitter_mutex.unlock();

“获取”线程代码：

while(true)
{
    Sleep(20);

    m_jitter_mutex.lock();
    speex_jitter_get(&jitter, (spx_int16_t*)pcm_short, NULL);
    m_pOut->Play(pcm_char, pcm_data_length);  // play the pcm data
    m_jitter_mutex.lock();
}

我也想使用speex库来做回波消除，但我不知道如何准确地实现它。非常感谢。

Answer 1

看一下样本吗？

放-取

https://github.com/xiph/speex/blob/master/speexclient/speexclient.c