fix(stream): bound FFmpeg memory buffers and propagate Blob backpressure

pkg/download/extension_engine_session.go

@@ -3,7 +3,6 @@ package download
 import (
 	"context"
 	"io"
-	"path/filepath"
 	"strings"
 	"sync"
 
@@ -127,12 +126,7 @@ func (d *Downloader) newExtensionEngine() (*engine.Engine, *engineSession) {
 	}{UserAgent: httpProtocol.DefaultUserAgent}
 	d.getProtocolConfig("http", &httpConfig)
 	userAgent := strings.TrimSpace(httpConfig.UserAgent)
-	tempDir := ""
-	if d.cfg.StorageDir != "" {
-		tempDir = filepath.Join(d.cfg.StorageDir, "temp", "ffmpeg")
-	}
 	e := engine.NewEngine(&engine.Config{
-		TempDir:       tempDir,
 		HTTPUserAgent: &userAgent,
 		ProxyConfig:   d.cfg.Proxy,
 		StreamConfig:  engineCfg,