obs-outputs: Add `video_id_t` value for 0

This will be initialized to 0 in various cases, so let's make that
a valid enum value (even if it's not valid in rtmp?)

plugins/obs-outputs/flv-mux.c

@@ -66,6 +66,10 @@ enum datatype_t {
 static void s_w4cc(struct serializer *s, enum video_id_t id)
 {
 	switch (id) {
+	case CODEC_NONE:
+		assert(0 && "Tried to serialize CODEC_NONE");
+		break;
+
 	case CODEC_AV1:
 		s_w8(s, 'a');
 		s_w8(s, 'v');

plugins/obs-outputs/flv-mux.h

@@ -22,6 +22,7 @@
 #define MILLISECOND_DEN 1000
 
 enum video_id_t {
+	CODEC_NONE = 0, // not valid in rtmp
 	CODEC_H264 = 1, // legacy & Y2023 spec
 	CODEC_AV1,      // Y2023 spec
 	CODEC_HEVC,

plugins/obs-outputs/flv-output.c

@@ -271,6 +271,12 @@ static bool write_video_header(struct flv_output *stream, size_t idx)
 		return false;
 
 	switch (stream->video_codec[idx]) {
+	case CODEC_NONE:
+		do_log(LOG_ERROR,
+		       "Codec not initialized for track %zu while sending header",
+		       idx);
+		return false;
+
 	case CODEC_H264:
 		packet.size = obs_parse_avc_header(&packet.data, header, size);
 		// Always send H.264 on track 0 as old style for compatibility.
@@ -541,6 +547,11 @@ static void flv_output_data(void *data, struct encoder_packet *packet)
 		}
 
 		switch (stream->video_codec[packet->track_idx]) {
+		case CODEC_NONE:
+			do_log(LOG_ERROR, "Codec not initialized for track %zu",
+			       packet->track_idx);
+			goto unlock;
+
 		case CODEC_H264:
 			obs_parse_avc_packet(&parsed_packet, packet);
 			break;

plugins/obs-outputs/rtmp-stream.c

@@ -815,6 +815,12 @@ static bool send_video_header(struct rtmp_stream *stream, size_t idx)
 		return false;
 
 	switch (stream->video_codec[idx]) {
+	case CODEC_NONE:
+		do_log(LOG_ERROR,
+		       "Codec not initialized for track %zu while sending header",
+		       idx);
+		return false;
+
 	case CODEC_H264:
 		packet.size = obs_parse_avc_header(&packet.data, header, size);
 		// Always send H.264 on track 0 as old style for compatibility.
@@ -1747,6 +1753,11 @@ static void rtmp_stream_data(void *data, struct encoder_packet *packet)
 		}
 
 		switch (stream->video_codec[packet->track_idx]) {
+		case CODEC_NONE:
+			do_log(LOG_ERROR, "Codec not initialized for track %zu",
+			       packet->track_idx);
+			return;
+
 		case CODEC_H264:
 			obs_parse_avc_packet(&new_packet, packet);
 			break;