GStreamer官方插件mpegpsdemux支持G.711

插件mpegpsdemux支持G.711"/>

GStreamer官方插件mpegpsdemux支持G.711

1、mpegpsdemux插件不支持G.711的原因 1.1、ISO13818支持的音频类型 1.2、GB28181支持的音视频类型 总结：由于官方插件mpegpsdemux插件是按ISO13818国际标准实现的，所以不支持G.711的编码需要修改源码。 2、源码分析并修改支持G.711 2.1、定义G.711宏

/* Stream type assignments**   0x00    ITU-T | ISO/IEC Reserved*   0x01    ISO/IEC 11172 Video*   0x02    ITU-T Rec. H.262 | ISO/IEC 13818-2 Video or*           ISO/IEC 11172-2 constrained parameter video*           stream*   0x03    ISO/IEC 11172 Audio*   0x04    ISO/IEC 13818-3 Audio*   0x05    ITU-T Rec. H.222.0 | ISO/IEC 13818-1*           private_sections*   0x06    ITU-T Rec. H.222.0 | ISO/IEC 13818-1 PES*           packets containing private data*   0x07    ISO/IEC 13522 MHEG*   0x08    ITU-T Rec. H.222.0 | ISO/IEC 13818-1 Annex A*           DSM CC*   0x09    ITU-T Rec. H.222.1*   0x0A    ISO/IEC 13818-6 type A*   0x0B    ISO/IEC 13818-6 type B*   0x0C    ISO/IEC 13818-6 type C*   0x0D    ISO/IEC 13818-6 type D*   0x0E    ISO/IEC 13818-1 auxiliary* 0x0F-0x7F ITU-T Rec. H.222.0 | ISO/IEC 13818-1 Reserved* 0x80-0xFF User Private*/
#define ST_RESERVED                     0x00
#define ST_VIDEO_MPEG1                  0x01
#define ST_VIDEO_MPEG2                  0x02
#define ST_AUDIO_MPEG1                  0x03
#define ST_AUDIO_MPEG2                  0x04
#define ST_PRIVATE_SECTIONS             0x05
#define ST_PRIVATE_DATA                 0x06
#define ST_MHEG                         0x07
#define ST_DSMCC                        0x08
#define ST_H222_1                       0x09
#define ST_AUDIO_ALAW                   0x90  //G.711
#define ST_AUDIO_MULAW                  0x91

2.2、解析流时创建G.711流的GstPad

static GstPsStream *
gst_ps_demux_create_stream(GstPsDemux * demux, gint id, gint stream_type,gint layer)
{GstPsStream *stream;GstPadTemplate *template;gchar *name;GstPsDemuxClass *klass = GST_PS_DEMUX_GET_CLASS(demux);GstCaps *caps;GstClockTime threshold = SEGMENT_THRESHOLD;GstEvent *event;gchar *stream_id;name = NULL;template = NULL;caps = NULL;GST_DEBUG_OBJECT(demux, "create stream id 0x%02x, type 0x%02x", id,stream_type);switch (stream_type) {case ST_VIDEO_MPEG1:case ST_VIDEO_MPEG2:case ST_VIDEO_MPEG4:case ST_GST_VIDEO_MPEG1_OR_2:{gint mpeg_version = 1;if (stream_type == ST_VIDEO_MPEG2 ||(stream_type == ST_GST_VIDEO_MPEG1_OR_2 &&  demux->is_mpeg2_pack)) {mpeg_version = 2;}if (stream_type == ST_VIDEO_MPEG4) {mpeg_version = 4;}template = klass->video_template;name = g_strdup_printf("video_%02x", id);caps = gst_caps_new_simple("video/mpeg","mpegversion", G_TYPE_INT, mpeg_version,"systemstream", G_TYPE_BOOLEAN, FALSE,"parsed", G_TYPE_BOOLEAN, FALSE, NULL);threshold = VIDEO_SEGMENT_THRESHOLD;break;}case ST_AUDIO_MPEG1:case ST_AUDIO_MPEG2:template = klass->audio_template;name = g_strdup_printf("audio_%02x", id);if (layer) {caps = gst_caps_new_simple("audio/mpeg","mpegversion", G_TYPE_INT, 1, "layer", G_TYPE_INT,  layer, NULL);}else {caps = gst_caps_new_simple("audio/mpeg","mpegversion", G_TYPE_INT, 1, NULL);}break;case ST_PRIVATE_SECTIONS:case ST_PRIVATE_DATA:case ST_MHEG:case ST_DSMCC:break;case ST_AUDIO_AAC_ADTS:template = klass->audio_template;name = g_strdup_printf("audio_%02x", id);caps = gst_caps_new_simple("audio/mpeg","mpegversion", G_TYPE_INT, 4,"stream-format", G_TYPE_STRING, "adts", NULL);break;case ST_AUDIO_AAC_LOAS:    // LATM/LOAS AAC syntaxtemplate = klass->audio_template;name = g_strdup_printf("audio_%02x", id);caps = gst_caps_new_simple("audio/mpeg","mpegversion", G_TYPE_INT, 4,"stream-format", G_TYPE_STRING, "loas", NULL);break;case ST_VIDEO_H264:template = klass->video_template;name = g_strdup_printf("video_%02x", id);caps = gst_caps_new_simple("video/x-h264","stream-format", G_TYPE_STRING, "byte-stream", NULL);threshold = VIDEO_SEGMENT_THRESHOLD;break;case ST_VIDEO_H265:template = klass->video_template;name = g_strdup_printf("video_%02x", id);caps = gst_caps_new_simple("video/x-h265","stream-format", G_TYPE_STRING, "byte-stream", NULL);threshold = VIDEO_SEGMENT_THRESHOLD;break;case ST_PS_AUDIO_AC3:template = klass->audio_template;name = g_strdup_printf("audio_%02x", id);caps = gst_caps_new_empty_simple("audio/x-private1-ac3");break;case ST_PS_AUDIO_DTS:template = klass->audio_template;name = g_strdup_printf("audio_%02x", id);caps = gst_caps_new_empty_simple("audio/x-private1-dts");break;case ST_PS_AUDIO_LPCM:template = klass->audio_template;name = g_strdup_printf("audio_%02x", id);caps = gst_caps_new_empty_simple("audio/x-private1-lpcm");break;case ST_PS_DVD_SUBPICTURE:template = klass->subpicture_template;name = g_strdup_printf("subpicture_%02x", id);caps = gst_caps_new_empty_simple("subpicture/x-dvd");break;case ST_GST_AUDIO_RAWA52:template = klass->audio_template;name = g_strdup_printf("audio_%02x", id);caps = gst_caps_new_empty_simple("audio/ac3");break;case ST_AUDIO_ALAW: //G.711支持template = klass->audio_template;name = g_strdup_printf("audio_%02x", id);caps = gst_caps_new_empty_simple("audio/x_alaw");break;case ST_AUDIO_MULAW:template = klass->audio_template;name = g_strdup_printf("audio_%02x", id);caps = gst_caps_new_empty_simple("audio/x-mulaw");break;default:break;}if (name == NULL || template == NULL || caps == NULL) {g_free(name);if (caps)gst_caps_unref(caps);return FALSE;}stream = g_new0(GstPsStream, 1);stream->id = id;stream->discont = TRUE;stream->need_segment = TRUE;stream->notlinked = FALSE;stream->type = stream_type;stream->pending_tags = NULL;stream->pad = gst_pad_new_from_template(template, name);stream->segment_thresh = threshold;gst_pad_set_event_function(stream->pad,GST_DEBUG_FUNCPTR(gst_ps_demux_src_event));gst_pad_set_query_function(stream->pad,GST_DEBUG_FUNCPTR(gst_ps_demux_src_query));gst_pad_use_fixed_caps(stream->pad);/* needed for set_caps to work */if (!gst_pad_set_active(stream->pad, TRUE)) {GST_WARNING_OBJECT(demux, "Failed to activate pad %" GST_PTR_FORMAT,stream->pad);}stream_id = gst_pad_create_stream_id_printf(stream->pad,  GST_ELEMENT_CAST(demux),"%02x", id);event = gst_pad_get_sticky_event(demux->sinkpad, GST_EVENT_STREAM_START,  0);if (event) {if (gst_event_parse_group_id(event, &demux->group_id))demux->have_group_id = TRUE;elsedemux->have_group_id = FALSE;gst_event_unref(event);}else if (!demux->have_group_id) {demux->have_group_id = TRUE;demux->group_id = gst_util_group_id_next();}event = gst_event_new_stream_start(stream_id);if (demux->have_group_id)gst_event_set_group_id(event, demux->group_id);gst_pad_push_event(stream->pad, event);g_free(stream_id);gst_pad_set_caps(stream->pad, caps);if (!stream->pending_tags)stream->pending_tags = gst_tag_list_new_empty();gst_pb_utils_add_codec_description_to_tag_list(stream->pending_tags,  NULL,caps);GST_DEBUG_OBJECT(demux, "create pad %s, caps %" GST_PTR_FORMAT, name,  caps);gst_caps_unref(caps);g_free(name);return stream;
}