FFmpeg multicast with multiple network interfaces - networking

Question

I have java-application as wrapper on FFmpeg. I need to capture mp2 multicast stream, convert it to mp3 and send converted multicast stream to another address.
It works well. But now I have two network interfaces. And one of them for internet/local network (eth1). Need to configure second network interface (eth2) to capture and send multicast streams.
But ffmpeg try to capture from first network interface by default. I can see packets in tcpdump, but ffmpeg don't capture it from eth2.
How can I specify interface for stream capturing and interface for stream sending?

Answer 1

This was solved by smcroute utility.
application.properties:
smcroute.config.file = /etc/smcroute.conf
RoutingConfig.java:
public class RoutingConfig {
private final File file;
public RoutingConfig(String filename) {
this.file = new File(filename);
}
public List<RoutingRecord> read() throws IOException {
List<String> lines = Files.readAllLines(file.toPath());
return lines.stream().map(RoutingRecord::new).collect(Collectors.toList());
}
public void write(List<RoutingRecord> records) throws IOException {
List<String> lines = records.stream().map(RoutingRecord::toString).collect(Collectors.toList());
Files.write(file.toPath(), lines);
}
}
RoutingRecord.java:
public class RoutingRecord {
private String sourceInterface;
private String multicastAddress;
private String sourceMulticastAddress;
private List<String> destinationInterfaces;
public RoutingRecord() {
}
public RoutingRecord(String line) {
String[] words = line.split(" ");
this.sourceInterface = words[2];
this.multicastAddress = words[4];
this.sourceMulticastAddress = words[6];
this.destinationInterfaces = new ArrayList<>(Arrays.asList(words).subList(8, words.length));
}
public RoutingRecord(String sourceInterface,
String multicastAddress,
String sourceMulticastAddress,
List<String> destinationInterfaces
) {
this.sourceInterface = sourceInterface;
this.multicastAddress = multicastAddress;
this.sourceMulticastAddress = sourceMulticastAddress;
this.destinationInterfaces = destinationInterfaces;
}
public String getSourceInterface() {return sourceInterface;}
public String getMulticastAddress() {return multicastAddress;}
public String getSourceMulticastAddress() {return sourceMulticastAddress;}
public List<String> getDestinationInterfaces() {return destinationInterfaces;}
public String getDestinationInterfacesLine() {return String.join(", ", destinationInterfaces);}
public RoutingRecord setSourceInterface(String sourceInterface) {
this.sourceInterface = sourceInterface;
return this;
}
public RoutingRecord setMulticastAddress(String multicastAddress) {
this.multicastAddress = multicastAddress;
return this;
}
public RoutingRecord setSourceMulticastAddress(String sourceMulticastAddress) {
this.sourceMulticastAddress = sourceMulticastAddress;
return this;
}
public RoutingRecord setDestinationInterfaces(List<String> destinationInterfaces) {
this.destinationInterfaces = destinationInterfaces;
return this;
}
#Override
public String toString() {
return "mroute from " + sourceInterface + " " +
"group " + multicastAddress + " " +
"source " + sourceMulticastAddress + " " +
"to " + String.join(" ", destinationInterfaces);
}
RoutingServiceImpl.java:
#Service
public class RoutingServiceImpl implements RoutingService {
private final Environment environment;
#Autowired
public RoutingServiceImpl(Environment environment) {
this.environment = environment;
}
#Override
public List<RoutingRecord> getRoutingLines() throws IOException {
String filename = environment.getProperty("smcroute.config.file");
RoutingConfig routingConfig = new RoutingConfig(filename);
return routingConfig.read();
}
#Override
public void saveRoutingLines(List<RoutingRecord> records) throws IOException {
String filename = environment.getProperty("smcroute.config.file");
RoutingConfig routingConfig = new RoutingConfig(filename);
routingConfig.write(records);
}
#Override
public void saveRoutingLine(RoutingRecord routingRecord) throws IOException {
String filename = environment.getProperty("smcroute.config.file");
RoutingConfig routingConfig = new RoutingConfig(filename);
List<RoutingRecord> records = routingConfig.read();
records.add(routingRecord);
routingConfig.write(records);
}
#Override
public void applyRoutes() throws IOException {
Runtime rt = Runtime.getRuntime();
rt.exec(new String[] {
"service",
"smcroute",
"restart"
});
}
}