These encoders:
* are supported by ~no hardware
* i can't think of any actual use for them in the apps we ship, and
* most importantly, fail to build with system aom/vpx.

The hardware *decoders*, on the other hand, are useful for Signal Messenger, and should work now.

--- src/media/gpu/vaapi/vaapi_video_encode_accelerator.cc.orig	2025-07-19 11:32:35.717979936 +0200
+++ src/media/gpu/vaapi/vaapi_video_encode_accelerator.cc	2025-08-15 14:42:43.908933011 +0200
@@ -46,13 +46,10 @@
 #include "media/gpu/gpu_video_encode_accelerator_helpers.h"
 #include "media/gpu/h264_dpb.h"
 #include "media/gpu/macros.h"
-#include "media/gpu/vaapi/av1_vaapi_video_encoder_delegate.h"
 #include "media/gpu/vaapi/h264_vaapi_video_encoder_delegate.h"
 #include "media/gpu/vaapi/vaapi_common.h"
 #include "media/gpu/vaapi/vaapi_utils.h"
 #include "media/gpu/vaapi/vaapi_wrapper.h"
-#include "media/gpu/vaapi/vp8_vaapi_video_encoder_delegate.h"
-#include "media/gpu/vaapi/vp9_vaapi_video_encoder_delegate.h"
 #include "media/gpu/vp8_reference_frame_vector.h"
 #include "media/gpu/vp9_reference_frame_vector.h"
 
@@ -233,8 +230,7 @@ EncoderStatus VaapiVideoEncodeAccelerato
   }
 
   const VideoCodec codec = VideoCodecProfileToVideoCodec(config.output_profile);
-  if (codec != VideoCodec::kH264 && codec != VideoCodec::kVP8 &&
-      codec != VideoCodec::kVP9 && codec != VideoCodec::kAV1) {
+  if (codec != VideoCodec::kH264) {
     MEDIA_LOG(ERROR, media_log.get())
         << "Unsupported profile: " << GetProfileName(config.output_profile);
     return {EncoderStatus::Codes::kEncoderInitializationError};
@@ -324,11 +320,6 @@ void VaapiVideoEncodeAccelerator::Initia
                      : VaapiWrapper::kEncodeVariableBitrate;
         }
         break;
-      case VideoCodec::kVP8:
-      case VideoCodec::kVP9:
-      case VideoCodec::kAV1:
-        mode = VaapiWrapper::kEncodeConstantQuantizationParameter;
-        break;
       default:
         NotifyError({EncoderStatus::Codes::kEncoderUnsupportedCodec,
                      "Unsupported codec: " + GetCodecName(output_codec_)});
@@ -380,24 +371,6 @@ void VaapiVideoEncodeAccelerator::Initia
         }
       }
       break;
-    case VideoCodec::kVP8:
-      if (!IsConfiguredForTesting()) {
-        encoder_ = std::make_unique<VP8VaapiVideoEncoderDelegate>(
-            vaapi_wrapper_, error_cb);
-      }
-      break;
-    case VideoCodec::kVP9:
-      if (!IsConfiguredForTesting()) {
-        encoder_ = std::make_unique<VP9VaapiVideoEncoderDelegate>(
-            vaapi_wrapper_, error_cb);
-      }
-      break;
-    case VideoCodec::kAV1:
-      if (!IsConfiguredForTesting()) {
-        encoder_ = std::make_unique<AV1VaapiVideoEncoderDelegate>(
-            vaapi_wrapper_, error_cb);
-      }
-      break;
     default:
       NOTREACHED() << "Unsupported codec type " << GetCodecName(output_codec_);
   }
@@ -896,19 +869,6 @@ VaapiVideoEncodeAccelerator::CreateEncod
       picture = base::MakeRefCounted<VaapiH264Picture>(
           reconstructed_surface->ReleaseAsVASurfaceHandle());
       break;
-    case VideoCodec::kVP8:
-      picture = base::MakeRefCounted<VaapiVP8Picture>(
-          reconstructed_surface->ReleaseAsVASurfaceHandle());
-      break;
-    case VideoCodec::kVP9:
-      picture = base::MakeRefCounted<VaapiVP9Picture>(
-          reconstructed_surface->ReleaseAsVASurfaceHandle());
-      break;
-    case VideoCodec::kAV1:
-      picture = base::MakeRefCounted<VaapiAV1Picture>(
-          /*display_va_surface=*/nullptr,
-          reconstructed_surface->ReleaseAsVASurfaceHandle());
-      break;
     default:
       return nullptr;
   }
--- src/media/gpu/vaapi/BUILD.gn.orig	2025-07-02 22:10:56.132470571 +0200
+++ src/media/gpu/vaapi/BUILD.gn	2025-07-11 18:17:18.866524759 +0200
@@ -36,8 +36,6 @@ source_set("vaapi") {
   sources = [
     "av1_vaapi_video_decoder_delegate.cc",
     "av1_vaapi_video_decoder_delegate.h",
-    "av1_vaapi_video_encoder_delegate.cc",
-    "av1_vaapi_video_encoder_delegate.h",
     "h264_vaapi_video_decoder_delegate.cc",
     "h264_vaapi_video_decoder_delegate.h",
     "h264_vaapi_video_encoder_delegate.cc",
@@ -67,12 +65,8 @@ source_set("vaapi") {
     "vaapi_webp_decoder.h",
     "vp8_vaapi_video_decoder_delegate.cc",
     "vp8_vaapi_video_decoder_delegate.h",
-    "vp8_vaapi_video_encoder_delegate.cc",
-    "vp8_vaapi_video_encoder_delegate.h",
     "vp9_vaapi_video_decoder_delegate.cc",
     "vp9_vaapi_video_decoder_delegate.h",
-    "vp9_vaapi_video_encoder_delegate.cc",
-    "vp9_vaapi_video_encoder_delegate.h",
   ]
   if (enable_hevc_parser_and_hw_decoder) {
     sources += [
@@ -96,8 +90,6 @@ source_set("vaapi") {
     "//media/gpu:video_frame_mapper_common",
     "//media/gpu/chromeos:common",
     "//mojo/public/cpp/bindings",
-    "//third_party/libaom:libaomrc",
-    "//third_party/libvpx:libvpxrc",
     "//third_party/libyuv",
     "//ui/gfx",
     "//ui/gfx/geometry",