所以我对此进行了一些研究，但找不到令人满意的答案。简而言之，部分（但不是全部）YouTube 视频没有声音。
我把这个更新放在这里是为了避免人们不得不浏览我之前放在这里的一堆垃圾。
玩了一会儿，我手动安装了 gstreamer1.0-libav。这解决了部分问题。我仍然无法使用 VP9 媒体。我有一个 H.264（High Profile）视频，它运行良好，但另一个 H.264（High Profile）视频却无法工作。一个可以工作的视频是 30fps，而另一个是 25fps。我一直用作示例的第三个视频被列为 H.264，但它也无法工作。
我一直使用 Totem 播放这些视频，以消除浏览器内可能出现的任何问题。我也尝试过使用 VLC Player，但结果相同。
需要注意的一点是，当视频播放不正常时，我听到的声音是电子耳语和尖叫声，找不到更好的词来形容。它正在尝试解码音频；但失败了。
结束更新 其余部分是原始帖子。
我确信只是缺少了某些编解码器或驱动程序未更新，但我还没有弄清楚，也在网上找不到任何针对此问题的具体信息。我发现了很多类似的问题，但它们都与无声音有关。我能听到声音，但不是所有声音。
顺便说一下，所讨论的浏览器是 Firefox。
我尝试过的操作：安装（并卸载并重新安装并重新启动）ubuntu-restricted-extras。确保软件和更新 > Ubuntu 软件复选框全部选中，包括主、宇宙、受限和多元宇宙，执行 Radeon 卡的 amdgpu-install 脚本（随后卸载，因为这搞砸了视频）
我的硬件设置：（抱歉，我本来想削减这个设置，但为了以防万一，还是把所有设置都放进去）
lspci-nn
00:00.0 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) Root Complex [1022:1450]
00:00.2 IOMMU [0806]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) I/O Memory Management Unit [1022:1451]
00:01.0 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-1fh) PCIe Dummy Host Bridge [1022:1452]
00:01.3 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) PCIe GPP Bridge [1022:1453]
00:02.0 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-1fh) PCIe Dummy Host Bridge [1022:1452]
00:03.0 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-1fh) PCIe Dummy Host Bridge [1022:1452]
00:03.2 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) PCIe GPP Bridge [1022:1453]
00:04.0 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-1fh) PCIe Dummy Host Bridge [1022:1452]
00:07.0 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-1fh) PCIe Dummy Host Bridge [1022:1452]
00:07.1 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) Internal PCIe GPP Bridge 0 to Bus B [1022:1454]
00:08.0 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-1fh) PCIe Dummy Host Bridge [1022:1452]
00:08.1 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) Internal PCIe GPP Bridge 0 to Bus B [1022:1454]
00:14.0 SMBus [0c05]: Advanced Micro Devices, Inc. [AMD] FCH SMBus Controller [1022:790b] (rev 59)
00:14.3 ISA bridge [0601]: Advanced Micro Devices, Inc. [AMD] FCH LPC Bridge [1022:790e] (rev 51)
00:18.0 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) Data Fabric: Device 18h; Function 0 [1022:1460]
00:18.1 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) Data Fabric: Device 18h; Function 1 [1022:1461]
00:18.2 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) Data Fabric: Device 18h; Function 2 [1022:1462]
00:18.3 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) Data Fabric: Device 18h; Function 3 [1022:1463]
00:18.4 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) Data Fabric: Device 18h; Function 4 [1022:1464]
00:18.5 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) Data Fabric: Device 18h; Function 5 [1022:1465]
00:18.6 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) Data Fabric: Device 18h; Function 6 [1022:1466]
00:18.7 Host bridge [0600]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) Data Fabric: Device 18h; Function 7 [1022:1467]
01:00.0 USB controller [0c03]: Advanced Micro Devices, Inc. [AMD] X370 Series Chipset USB 3.1 xHCI Controller [1022:43b9] (rev 02)
01:00.1 SATA controller [0106]: Advanced Micro Devices, Inc. [AMD] X370 Series Chipset SATA Controller [1022:43b5] (rev 02)
01:00.2 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] X370 Series Chipset PCIe Upstream Port [1022:43b0] (rev 02)
02:00.0 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] 300 Series Chipset PCIe Port [1022:43b4] (rev 02)
02:02.0 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] 300 Series Chipset PCIe Port [1022:43b4] (rev 02)
02:03.0 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] 300 Series Chipset PCIe Port [1022:43b4] (rev 02)
02:04.0 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] 300 Series Chipset PCIe Port [1022:43b4] (rev 02)
02:05.0 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] 300 Series Chipset PCIe Port [1022:43b4] (rev 02)
02:06.0 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] 300 Series Chipset PCIe Port [1022:43b4] (rev 02)
02:07.0 PCI bridge [0604]: Advanced Micro Devices, Inc. [AMD] 300 Series Chipset PCIe Port [1022:43b4] (rev 02)
03:00.0 USB controller [0c03]: ASMedia Technology Inc. ASM1143 USB 3.1 Host Controller [1b21:1343]
04:00.0 Ethernet controller [0200]: Intel Corporation I211 Gigabit Network Connection [8086:1539] (rev 03)
**0a:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Cayman PRO [Radeon HD 6950] [1002:6719]
0a:00.1 Audio device [0403]: Advanced Micro Devices, Inc. [AMD/ATI] Cayman/Antilles HDMI Audio [Radeon HD 6930/6950/6970/6990] [1002:aa80]**
0b:00.0 Non-Essential Instrumentation [1300]: Advanced Micro Devices, Inc. [AMD] Zeppelin/Raven/Raven2 PCIe Dummy Function [1022:145a]
0b:00.2 Encryption controller [1080]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) Platform Security Processor [1022:1456]
0b:00.3 USB controller [0c03]: Advanced Micro Devices, Inc. [AMD] Zeppelin USB 3.0 Host controller [1022:145f]
0c:00.0 Non-Essential Instrumentation [1300]: Advanced Micro Devices, Inc. [AMD] Zeppelin/Renoir PCIe Dummy Function [1022:1455]
0c:00.2 SATA controller [0106]: Advanced Micro Devices, Inc. [AMD] FCH SATA Controller [AHCI mode] [1022:7901] (rev 51)
**0c:00.3 Audio device [0403]: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) HD Audio Controller [1022:1457]**
sudo lshw-c 多媒体 *-多媒体
description: Audio device
product: Cayman/Antilles HDMI Audio [Radeon HD 6930/6950/6970/6990]
vendor: Advanced Micro Devices, Inc. [AMD/ATI]
physical id: 0.1
bus info: pci@0000:0a:00.1
version: 00
width: 64 bits
clock: 33MHz
capabilities: pm pciexpress msi bus_master cap_list
configuration: driver=snd_hda_intel latency=0
resources: irq:79 memory:fcf40000-fcf43fff
*-multimedia
description: Audio device
product: Family 17h (Models 00h-0fh) HD Audio Controller
vendor: Advanced Micro Devices, Inc. [AMD]
physical id: 0.3
bus info: pci@0000:0c:00.3
version: 00
width: 32 bits
clock: 33MHz
capabilities: pm pciexpress msi bus_master cap_list
configuration: **driver=snd_hda_intel** latency=0
resources: irq:81 memory:fce00000-fce07fff
sudo lshw -c 视频 *-展示
描述：VGA兼容控制器产品：开曼 PRO [Radeon HD 6950] 供应商：Advanced Micro Devices, Inc. [AMD/ATI] 物理 ID：0 总线信息：pci@0000:0a:00.0 版本：00 宽度：64 位 时钟：33MHz 功能：pm pciexpress msi vga_controller bus_master cap_list rom 配置：驱动程序=radeon延迟=0 资源：irq：83 内存：e0000000-efffffff 内存：fcf20000-fcf3ffff ioport：d000（size=256） 内存：c0000-dffff