audio - gstreamer 多通道大于 8 个通道
问题描述
下午好，到目前为止，我一直在使用 gstreamer 流式传输 8 通道音频，没有任何问题。我大胆地生成 8 个单声道并导出一个 wav 文件。
最近有人要求我支持 16 个频道，但我惊讶地发现不支持 16 个频道（或 8 个以上的频道）。用于流式传输使用的 wav 文件的命令行 gstreamer 命令如下所示：
GST_DEBUG=3 gst-launch-1.0 filesrc location=~/Desktop/8ch_16_test_diagwav.wav ! decodebin ! audioconvert ! audioresample ! audioconvert ! audio/x-raw,format=S16BE,rate=48000,channels=16 ! filesink location=/tmp/filesink0
使用 16 通道文件运行时出现以下错误：
Setting pipeline to PAUSED ...
0:00:00.041995106 3534 0x55b0024a4e10 WARN basesrc gstbasesrc.c:3583:gst_base_src_start_complete:<filesrc0> pad not activated yet
Pipeline is PREROLLING ...
0:00:00.046842761 3534 0x7f833806ec00 FIXME default gstutils.c:3981:gst_pad_create_stream_id_internal:<wavparse0:src> Creating random stream-id, consider implementing a deterministic way of creating a stream-id
0:00:00.091236225 3534 0x7f833806ec00 WARN audio-resampler audio-resampler.c:274:convert_taps_gint16_c: can't find exact taps
0:00:00.091319797 3534 0x7f833806ec00 WARN audioconvert gstaudioconvert.c:654:gst_audio_convert_fixate_channels:<audioconvert1> invalid or unexpected channel-positions
0:00:00.091329274 3534 0x7f833806ec00 ERROR audioconvert gstaudioconvert.c:668:gst_audio_convert_fixate_channels:<audioconvert1> Have no default layout for 16 channels
0:00:00.091339971 3534 0x7f833806ec00 ERROR audio-info audio-info.c:304:gst_audio_info_from_caps: no channel-mask property given
0:00:00.091344101 3534 0x7f833806ec00 ERROR audioconvert gstaudioconvert.c:778:gst_audio_convert_set_caps:<audioconvert1> invalid output caps
0:00:00.091356433 3534 0x7f833806ec00 WARN basetransform gstbasetransform.c:1362:gst_base_transform_setcaps:<audioconvert1> FAILED to configure incaps audio/x-raw, format=(string)S16LE, layout=(string)interleaved, channels=(int)8, channel-mask=(bitmask)0x0000000000000c3f, rate=(int)48000 and outcaps audio/x-raw, layout=(string)interleaved, rate=(int)48000, format=(string)S16BE, channels=(int)16
0:00:00.091398546 3534 0x7f833806ec00 WARN audioconvert gstaudioconvert.c:654:gst_audio_convert_fixate_channels:<audioconvert1> invalid or unexpected channel-positions
0:00:00.091404430 3534 0x7f833806ec00 ERROR audioconvert gstaudioconvert.c:668:gst_audio_convert_fixate_channels:<audioconvert1> Have no default layout for 16 channels
0:00:00.091411526 3534 0x7f833806ec00 ERROR audio-info audio-info.c:304:gst_audio_info_from_caps: no channel-mask property given
0:00:00.091415084 3534 0x7f833806ec00 ERROR audioconvert gstaudioconvert.c:778:gst_audio_convert_set_caps:<audioconvert1> invalid output caps
0:00:00.091423006 3534 0x7f833806ec00 WARN basetransform gstbasetransform.c:1362:gst_base_transform_setcaps:<audioconvert1> FAILED to configure incaps audio/x-raw, format=(string)S16LE, layout=(string)interleaved, channels=(int)8, channel-mask=(bitmask)0x0000000000000c3f, rate=(int)48000 and outcaps audio/x-raw, layout=(string)interleaved, rate=(int)48000, format=(string)S16BE, channels=(int)16
0:00:00.091461862 3534 0x7f833806ec00 WARN audioconvert gstaudioconvert.c:654:gst_audio_convert_fixate_channels:<audioconvert1> invalid or unexpected channel-positions
0:00:00.091467389 3534 0x7f833806ec00 ERROR audioconvert gstaudioconvert.c:668:gst_audio_convert_fixate_channels:<audioconvert1> Have no default layout for 16 channels
0:00:00.091473940 3534 0x7f833806ec00 ERROR audio-info audio-info.c:304:gst_audio_info_from_caps: no channel-mask property given
0:00:00.091477330 3534 0x7f833806ec00 ERROR audioconvert gstaudioconvert.c:778:gst_audio_convert_set_caps:<audioconvert1> invalid output caps
0:00:00.091484711 3534 0x7f833806ec00 WARN basetransform gstbasetransform.c:1362:gst_base_transform_setcaps:<audioconvert1> FAILED to configure incaps audio/x-raw, format=(string)S16LE, layout=(string)interleaved, channels=(int)8, channel-mask=(bitmask)0x0000000000000c3f, rate=(int)48000 and outcaps audio/x-raw, layout=(string)interleaved, rate=(int)48000, format=(string)S16BE, channels=(int)16
0:00:00.091521324 3534 0x7f833806ec00 WARN audioconvert gstaudioconvert.c:654:gst_audio_convert_fixate_channels:<audioconvert1> invalid or unexpected channel-positions
0:00:00.091526722 3534 0x7f833806ec00 ERROR audioconvert gstaudioconvert.c:668:gst_audio_convert_fixate_channels:<audioconvert1> Have no default layout for 16 channels
0:00:00.091533191 3534 0x7f833806ec00 ERROR audio-info audio-info.c:304:gst_audio_info_from_caps: no channel-mask property given
0:00:00.091536562 3534 0x7f833806ec00 ERROR audioconvert gstaudioconvert.c:778:gst_audio_convert_set_caps:<audioconvert1> invalid output caps
0:00:00.091543448 3534 0x7f833806ec00 WARN basetransform gstbasetransform.c:1362:gst_base_transform_setcaps:<audioconvert1> FAILED to configure incaps audio/x-raw, format=(string)S16LE, layout=(string)interleaved, channels=(int)8, channel-mask=(bitmask)0x0000000000000c3f, rate=(int)48000 and outcaps audio/x-raw, layout=(string)interleaved, rate=(int)48000, format=(string)S16BE, channels=(int)16
0:00:00.091554349 3534 0x7f833806ec00 WARN wavparse gstwavparse.c:2293:gst_wavparse_loop:<wavparse0> error: Internal data stream error.
0:00:00.091558663 3534 0x7f833806ec00 WARN wavparse gstwavparse.c:2293:gst_wavparse_loop:<wavparse0> error: streaming stopped, reason not-negotiated (-4)
ERROR: from element /GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstWavParse:wavparse0: Internal data stream error.
Additional debug info:
gstwavparse.c(2293): gst_wavparse_loop (): /GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstWavParse:wavparse0:
streaming stopped, reason not-negotiated (-4)
0:00:00.091614021 3534 0x7f833806ec00 WARN audioconvert gstaudioconvert.c:654:gst_audio_convert_fixate_channels:<audioconvert1> invalid or unexpected channel-positions
ERROR: pipeline doesn't want to preroll.
Setting pipeline to NULL ...
0:00:00.091619464 3534 0x7f833806ec00 ERROR audioconvert gstaudioconvert.c:668:gst_audio_convert_fixate_channels:<audioconvert1> Have no default layout for 16 channels
0:00:00.091662384 3534 0x7f833806ec00 ERROR audio-info audio-info.c:304:gst_audio_info_from_caps: no channel-mask property given
0:00:00.091681343 3534 0x7f833806ec00 ERROR audioconvert gstaudioconvert.c:778:gst_audio_convert_set_caps:<audioconvert1> invalid output caps
0:00:00.091701845 3534 0x7f833806ec00 WARN basetransform gstbasetransform.c:1362:gst_base_transform_setcaps:<audioconvert1> FAILED to configure incaps audio/x-raw, format=(string)S16LE, layout=(string)interleaved, channels=(int)8, channel-mask=(bitmask)0x0000000000000c3f, rate=(int)48000 and outcaps audio/x-raw, layout=(string)interleaved, rate=(int)48000, format=(string)S16BE, channels=(int)16
0:00:00.091767321 3534 0x7f833806ec00 WARN audioconvert gstaudioconvert.c:654:gst_audio_convert_fixate_channels:<audioconvert1> invalid or unexpected channel-positions
0:00:00.091773142 3534 0x7f833806ec00 ERROR audioconvert gstaudioconvert.c:668:gst_audio_convert_fixate_channels:<audioconvert1> Have no default layout for 16 channels
0:00:00.091779617 3534 0x7f833806ec00 ERROR audio-info audio-info.c:304:gst_audio_info_from_caps: no channel-mask property given
0:00:00.091797568 3534 0x7f833806ec00 ERROR audioconvert gstaudioconvert.c:778:gst_audio_convert_set_caps:<audioconvert1> invalid output caps
0:00:00.091805352 3534 0x7f833806ec00 WARN basetransform gstbasetransform.c:1362:gst_base_transform_setcaps:<audioconvert1> FAILED to configure incaps audio/x-raw, format=(string)S16LE, layout=(string)interleaved, channels=(int)8, channel-mask=(bitmask)0x0000000000000c3f, rate=(int)48000 and outcaps audio/x-raw, layout=(string)interleaved, rate=(int)48000, format=(string)S16BE, channels=(int)16
Freeing pipeline ...
当使用 8channel 文件和 channel =8 以及从同一个 audacity 项目生成的 wav 文件时，一切都很好。
现在测试
linux
gst-launch-1.0 version 1.14.4
GStreamer 1.14.4
是否根本不可能从命令行使用 gstreamer 流式传输 16ch wav 文件？我曾尝试查看各种标志，例如交错、通道位置等，但没有足够的经验来临时知道可能需要什么。
任何帮助或链接都会受到重视。
解决方案
经过相当多的搜索和试验，我终于找到了一个可行的解决方案。
gst-launch-1.0 filesrc location=16ch_16bit_10s.wav ! decodebin ! capssetter caps="audio/x-raw,channels=16,rate=48000,channel-mask=(bitmask)0xffff" ! audioconvert ! audioresample ! "audio/x-raw,rate=48000,format=S16BE" ! queue ! capssetter caps="audio/x-raw,channels=16,rate=48000,channel-mask=(bitmask)0xffff" ! audioconvert ! audioresample ! filesink location=audiosink
其中位掩码值 = (2^channels) - 1 以十六进制字符串格式。
这主要是通过跟踪和错误发现的，使用以下作为参考： interleaving 4 channels of audio into vorbisenc or opusenc in gstreamer
不幸的是，我没有足够的经验（或足够聪明）来完全理解为什么会这样。capsetter 实际上做了什么以及为什么"audio/x-raw,rate=48000,format=S16BE"上游和下游之间需要 an 是任何人的猜测。如果有人可以编辑/评论更好的解释可能会很好？
使用此解决方案，我可以在 16-24 位和 1、2、4、8、16 通道之间切换。