在项目中处理音频,有时候会出现音频源没数据,但又不能中断输入音频数据给编码器,否则很有可能就出现声音与画面不同步的严重问题。所以尝试了几种构造静音帧的方法,最终找到了ffmpeg上面,废话也不多话,直接上一段代码:
AVFrame *alloc_silence_frame(int channels, int samplerate, int format)
{
AVFrame *frame;
int32_t ret;
frame = av_frame_alloc();
if(!frame)
{
return NULL;
}
frame->sample_rate = samplerate;
frame->format = format; /*默认的format:AV_SAMPLE_FMT_FLTP*/
frame->channel_layout = av_get_default_channel_layout(channels);
frame->channels = channels;
frame->nb_samples = AAC_NBSAMPLE; /*默认的sample大小:1024*/
ret = av_frame_get_buffer(frame, 0);
if(ret < 0)
{
av_frame_free(&frame);
return NULL;
}
av_samples_set_silence(frame->data, 0, frame->nb_samples, frame->channels,frame->format);
return frame;
}