gstreamer：将音频流拆分为文件

Question

我有一个音频流，我想将其保存为按时间分割的单个可播放文件。

如果我没理解错的话，splitmuxsink 会对视频文件执行此操作，但不会对纯音频文件执行此操作。

这里有一些关于如何完成此操作的提示： http://gstreamer-devel.966125.n4.nabble.com/Dynamically-updating-filesink-location-at-run-time-on-the-fly-td4660569.html 我正在努力重现这一点，并且提到的功能适用于 gstreamer-0.1。

Answer 1

从splitmuxsink的描述来看似乎包含音频：

Pad Templates:
  SINK template: 'video'
    Availability: On request
    Capabilities:
      ANY

  SINK template: 'audio_%u'
    Availability: On request
    Capabilities:
      ANY

  SINK template: 'subtitle_%u'
    Availability: On request
    Capabilities:
      ANY

所以我不明白为什么只有音频文件不能使用它。特别是因为 视频文件 通常被认为是只有音频的视频文件。

编辑下面的命令应该生成 AC3/MP4 个文件，每 1 分钟长：

gst-launch-1.0 -e audiotestsrc ! avenc_ac3 ! ac3parse ! mux.audio_0 splitmuxsink name=mux max-size-time=60000000000 location=out_%d.mp4

Answer 2

我使用 C 中的动态流水线进行了 ogg 编码的音频文件拆分。

Florian Zwoch 在之前的回答中展示了 splitmuxsink 如何拆分音频流。

使用动态管道拆分文件的解决方法：

#include <stdio.h>                                                              

#define GLIB_DISABLE_DEPRECATION_WARNINGS                                       
#include <gst/gst.h>                                                            

static GstElement *pipeline;                                                    
static GstPad *queue_src_pad;                                                   
static GstElement *bins[2];                                                     
static GstPad *bin_pads[2];                                                     
static GstElement *filesink[2];                                                 

static size_t current_bin = 0;                                                  
static size_t current_file = 0;                                                 

static GstPadProbeReturn                                                        
    pad_probe_cb (GstPad * pad, GstPadProbeInfo * info, gpointer user_data) {   
    gst_pad_remove_probe (pad, GST_PAD_PROBE_INFO_ID (info));                   

    gst_pad_unlink(queue_src_pad, bin_pads[current_bin]);                       
    gst_pad_send_event(bin_pads[current_bin], gst_event_new_eos());             
    gst_bin_remove(GST_BIN(pipeline), bins[current_bin]);                       
    gst_element_set_state(bins[current_bin], GST_STATE_NULL);                   

    current_file++;                                                             
    current_bin = (current_file % 2);                                           

    {                                                                           
       char file_location[32];                                                  
       sprintf(file_location, "recording_%ld.ogg", current_file);               
       g_object_set(G_OBJECT(                                                   
            filesink[current_bin]), "location", file_location, NULL);           

       printf("now writing to %s\n", file_location);                            
    }                                                                           

    gst_bin_add(GST_BIN(pipeline), bins[current_bin]);                          
    gst_pad_link(queue_src_pad, bin_pads[current_bin]);                         
    gst_element_sync_state_with_parent(bins[current_bin]);                      

    return GST_PAD_PROBE_OK;                                                    
}

static gboolean timeout_cb(gpointer user_data) {                                
    gst_pad_add_probe (queue_src_pad, GST_PAD_PROBE_TYPE_BLOCK_DOWNSTREAM,      
        pad_probe_cb, NULL, NULL);                                              

    return TRUE;                                                                
}                                                                               

int main(int argc, char *argv[]) {                                              
    GstElement *audiosrc, *queue;                                               
    GstElement *vorbisenc[2], *oggmux[2];                                       

    GstBus *bus;                                                                
    GMainLoop *loop;                                                            

    gst_init (&argc, &argv);                                                    

    //audiosrc = gst_element_factory_make("audiotestsrc", "audiosrc");          
    //g_object_set (G_OBJECT (audiosrc), "is-live", TRUE, NULL);                
    audiosrc = gst_element_factory_make("pulsesrc", "audiosrc");                

    queue = gst_element_factory_make("queue", "queue");                         

    bins[0] = gst_bin_new ("bin0");                                             
    bins[1] = gst_bin_new ("bin1");                                             

    vorbisenc[0] = gst_element_factory_make("vorbisenc", "vorbisenc0");         
    vorbisenc[1] = gst_element_factory_make("vorbisenc", "vorbisenc1");         

    oggmux[0] = gst_element_factory_make("oggmux", "oggmux0");                  
    oggmux[1] = gst_element_factory_make("oggmux", "oggmux1");                  

    filesink[0] = gst_element_factory_make("filesink", "filesink0");            
    filesink[1] = gst_element_factory_make("filesink", "filesink1");            

    pipeline = gst_pipeline_new ("test-pipeline");                              

    if (!pipeline || !audiosrc || !queue                                        
            || !vorbisenc[0] || !oggmux[0] || !filesink[0]                      
            || !vorbisenc[1] || !oggmux[1] || !filesink[1]                      
            ) {                                                                 
        g_printerr ("not all elements could be created\n");                     
        return -1;                                                              
    }
    gst_bin_add_many(                                                           
        GST_BIN(bins[0]), vorbisenc[0], oggmux[0], filesink[0], NULL);          
    gst_bin_add_many(                                                           
        GST_BIN(bins[1]), vorbisenc[1], oggmux[1], filesink[1], NULL);          
    gst_bin_add_many(                                                           
        GST_BIN(pipeline), audiosrc, queue, bins[0], NULL);                     

    g_assert (gst_element_link(audiosrc, queue));                               

    g_assert (gst_element_link_many(                                            
        vorbisenc[0], oggmux[0], filesink[0], NULL));                           
    g_assert (gst_element_link_many(                                            
        vorbisenc[1], oggmux[1], filesink[1], NULL));                           

    {                                                                           
        GstPad* pad = gst_element_get_static_pad(vorbisenc[0], "sink");         
        gst_element_add_pad(bins[0], gst_ghost_pad_new("sink", pad));           
        gst_object_unref(pad);                                                  
    }                                                                           
    {                                                                           
        GstPad* pad = gst_element_get_static_pad(vorbisenc[1], "sink");         
        gst_element_add_pad(bins[1], gst_ghost_pad_new("sink", pad));           
        gst_object_unref(pad);                                                  
    }                                                                           
    bin_pads[0] = gst_element_get_static_pad(bins[0], "sink");                  
    bin_pads[1] = gst_element_get_static_pad(bins[1], "sink");                  

    current_bin = 0;                                                            
    gst_element_link(queue, bins[current_bin]);                                 
    g_object_set (filesink[current_bin], "location", "recording_0.ogg", NULL);  

    queue_src_pad = gst_element_get_static_pad (queue, "src");                  

    bus = gst_element_get_bus (pipeline);                                       
    gst_element_set_state (pipeline, GST_STATE_PLAYING);                        

    loop = g_main_loop_new (NULL, FALSE);                                       
    g_timeout_add_seconds (3, timeout_cb, NULL);                                
    g_main_loop_run (loop);                                                     

    gst_object_unref (bus);                                                     
    gst_element_set_state (pipeline, GST_STATE_NULL);                           

    gst_object_unref (pipeline);                                                
    return 0;                                                                   
}

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